Paper 5 Physics Tips

Amur Leopard

Panthera pardus orientalis

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Cross River Gorilla Gorilla gorilla diehli

People usually think of leopards in the savannas of Africa but in the Russian Far East, a rare subspecies has adapted to life in the temperate forests that make up the northern-most part of the species’ range. Similar to other leopards, the Amur leopard can run at speeds of up to 37 miles per hour.The Amur leopard is solitary. Nimble-footed and strong, it carries and hides unfinished kills so that they are not taken by other predators. It has been reported that some males stay with females after mating, and may even help with rearing the young. Several males sometimes follow and fight over a female. They live for 10-15 years, and in captivity up to 20 years.

European hunters are responsible for the early decline of black rhino populations. It was not uncommon for five or six rhinos to be killed in a day for food or simply for amusement.

European settlers that arrived in Africa in the early 20th century to colonize and establish farms and plantations continued this senseless slaughter. Most people regarded

rhinos as vermin and exterminated them at all costs.

This subspecies of the western gorilla is very similar in appearance to the more numerous western lowland gorilla, but subtle differences can be found in the skull and tooth dimensions. Cross River gorillas live in a region populated by many humans who have encroached upon the gorilla’s territory—clearing forests for timber and to create fields for agriculture and livestock. Poaching occurs in the forests as well, and the loss of even a few of these gorillas has a detrimental effect on such a small population. Efforts to protect these animals are focused on securing the forests that house them.

Hawksbill Turtle Eretmochelys imbricata

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Javan rhinos are the most threatened of the five rhino species, with as few as 35 individuals surviving in Ujung Kulon National Park in Java, Indonesia. Vietnam’s last Javan rhino was poached in 2010. The Javan rhino is a dusky grey color and has a single horn of up to about 10 inches. Their skin has a number of loose folds giving the appearance of armor plating. This species is very similar in appearance to the closely-related greater-one rhinoceros, but has a much smaller head and less apparent skin folds.

Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Mountain Gorilla Gorilla beringei beringei

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South China Tiger Panthera tigris amoyensis

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Saola (pronounced: sow-la) are recognized by two parallel horns with sharp ends, which can reach 20 inches in length and are found on both males and females. Meaning “spindle horns” in Vietnamese, they are a cousin of cattle but

resemble an antelope. Saola have striking white markings on the face and large maxillary glands on the muzzle, which could be used to mark territory or attract mates. They are found only in the Annamite Mountains of Vietnam and Laos.

The South China tiger population was estimated to number 4,000 individuals in the early 1950s. In the next few decades, thousands were killed as the subspecies was hunted as a pest. The Chinese government banned hunting in 1979. By 1996 the population was estimated to be just 30-80

individuals.

Today the South China tiger is considered by scientists to be “functionally extinct,” as it has not been sighted in the wild for more than 25 years.

As their name implies, mountain gorillas live in forests high in the mountains, at elevations of 8,000 to 13,000 feet. They have thicker fur, and more of it, compared to other great apes. The fur helps them to survive in a habitat where

temperatures often drop below freezing. But as humans have moved more and more into the gorillas’ territory, the gorillas have been pushed farther up into the mountains for longer periods, forcing them to endure dangerous and sometimes deadly conditions.

Sumatran Elephant Elephas maximus sumatranus

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Historically, the Sumatran orangutan was distributed over the entire island of Sumatra and further south into Java. The species' range is now restricted to the north of the island with a majority in the provinces of North Sumatra and Aceh. Of the nine existing populations of Sumatran orangutans, only seven have prospects of long-term viability, each with an estimated 250 or more individuals. Only three populations contain more than 1,000 orangutans. Orangutans that were confiscated from the illegal trade or as pets are being

reintroduced to Bukit Tigapuluh National Park. They number around 70 and are reproducing.

Sumatran rhinos are the smallest of the living rhinoceroses and the only Asian rhino with two horns. They are covered with long hair and are more closely related to the extinct woolly rhinos than any of the other rhino species alive today. Calves are born with a dense covering that turns reddish brown in young adults and becomes sparse, bristly and almost black in older animals. Sumatran rhinos compete with the Javan rhino for the unenviable title of most threatened rhino species. While surviving in greater numbers than the Javan rhino, Sumatran rhinos are more threatened by poaching. There is no indication that the population is stable and just two captive females have reproduced in the last 15 y years.

Sumatran elephants feed on a variety of plants and deposit seeds wherever they go, contributing to a healthy forest ecosystem. They also share their lush forest habitat with several other endangered species, such as the Sumatran rhino, tiger, and orangutan, and countless other species that all benefit from an elephant population that thrives in a healthy habitat.

Sumatran Tiger Panthera tigris sumatrae

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Western Lowland Gorilla Gorilla gorilla gorilla

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The vaquita has a large dark ring around its eyes and dark patches on its lips that form a thin line from the mouth to the pectoral fins. Its dorsal surface is dark gray, sides pale gray and ventral surface white with long, light gray markings. Newborn vaquita have darker coloration and a wide gray fringe of color that runs from the head to the dorsal flukes, passing through the dorsal and pectoral fins.

Vaquita are under threat from the fishing industry. They often die after being caught in gillnets, a problem known as

bycatch.

Accelerating deforestation and rampant poaching mean this noble creature could end up like its extinct Javan and

Balinese relatives.Sumatran tigers are the smallest surviving tiger subspecies and are distinguished by heavy black stripes on their orange coats. They are protected by law in Indonesia, with tough provisions for jail time and steep fines. But despite increased efforts in tiger conservation—including law enforcement and antipoaching capacity—a substantial market remains in Sumatra and the rest of Asia for tiger parts and products. Sumatran tigers are losing their habitat and prey fast, and poaching shows no sign of decline.

Western lowland gorillas can be distinguished from other gorilla subspecies by their slightly smaller size, their brown-grey coats and auburn chests. They also have wider skulls with more pronounced brow ridges and smaller ears. Large numbers have not protected the western lowland gorilla from decline. Because of poaching and disease, the gorilla’s numbers have declined by more than 60% over the last 20 to 25 years. Even if all of the threats to western lowland gorillas were removed, scientists calculate that the population would require some 75 years to recover.

Yangtze Finless Porpoise Neophocaena asiaeorientalis ...

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African Wild Dog Lycaon pictus

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Amur Tiger Panthera tigris altaica

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Amur tigers were once found throughout the Russian Far East, northern China, and the Korean peninsula. By the 1940s, hunting had driven the Amur tiger to the brink of extinction—with no more than 40 individuals remaining in the

wild. The subspecies was saved when Russia became the first country in the world to grant the tiger full protection.

Wild dogs are social and gather in packs of around ten individuals, but some packs number more than 40. They are

opportunistic predators that hunt medium-sized ruminants, such as gazelles. In a sprint, African wild dogs can reach

speeds of more than 44 miles per hour.

The Yangtze River, the longest river in Asia, used to be one of the only two rivers in the world that was home to two different species of dolphin—the Yangtze finless porpoise and the Baiji dolphin. However, in 2006 the Baiji dolphin was declared functionally extinct. This was the first time in history that an entire species of dolphin had been wiped off the planet because of human activity. Its close cousin, the Yangtze finless porpoise, is known for its mischievous smile and has a level of intelligence comparable to that of a gorilla.

Asian Elephant Elephas maximus indicus

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Bengal Tiger Panthera tigris tigris

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Black Spider Monkey Ateles paniscus

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The Bengal tiger is found primarily in India with smaller populations in Bangladesh, Nepal, Bhutan, China and

Myanmar. It is the most numerous of all tiger subspecies with fewer than 2,500 left in the wild. The creation of India’s tiger reserves in the 1970s helped to stabilize numbers, but poaching to meet a growing demand from Asia in recent years has once again put the Bengal tiger at risk. The

mangroves of the Sundarbans—shared between Bangladesh and India—are the only mangrove forests where tigers are found. The Sundarbans are increasingly threatened by sea level rise as a result of climate change.

Asian elephants are extremely sociable, forming groups of six to seven related females that are led by the oldest female, the matriarch. Like African elephants, these groups occasionally join others to form herds, although these associations are relatively transient.

More than two thirds of an elephant’s day may be spent feeding on grasses, but large amounts of tree bark, roots, leaves and small stems are also eaten. Cultivated crops such as bananas, rice and sugarcane are favorite foods. Elephants are always close to a source of fresh water because they need to drink at least once a day.

The black spider monkey—also known as the Guiana or red-faced spider monkey—is found in eastern South America in areas north of the Amazon River. They are one of seven species of spider monkeys found in Latin America and one of the largest primate species in South America.

Black-footed Ferret Mustela nigripes

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Bluefin are the largest tuna and can live up to 40 years. They migrate across oceans and can dive more than 4,000 feet. Bluefin tuna are made for speed: built like torpedoes, have retractable fins and their eyes are set flush to their body. They are tremendous predators from the moment they hatch, seeking out schools of fish like herring, mackerel and even eels. They hunt by sight and have the sharpest vision of any bony fish. There are three species of bluefin: Atlantic (the largest and most endangered), Pacific, and Southern. Most catches of the Atlantic bluefin tuna are taken from the Mediterranean Sea, which is the most important bluefin tuna fishery in the world.

The blue whale is the largest animal on the planet, weighing as much as 200 tons (approximately 33 elephants). The blue whale has a heart the size of a Volkswagen Beetle. Its stomach can hold one ton of krill and it needs to eat about four tons of krill each day. They are the loudest animals on Earth and are even louder than a jet engine. Their calls reach 188 decibels, while a jet reaches 140 decibels. Their low frequency whistle can be heard for hundreds of miles and is probably used to attract other blue whales.

Once thought to be globally extinct, black-footed ferrets are making a comeback. For the last thirty years, concerted efforts from many state and federal agencies, zoos, Native American tribes, conservation organizations and private landowners have given black-footed ferrets a second chance for survival. Today, recovery efforts have helped restore the black-footed ferret population to nearly 1,000 animals across North America. Although great strides have been made to recover the black-footed ferret, habitat loss and disease remain key threats to this highly endangered species.

Bonobo Pan paniscus

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Borneo Pygmy Elephant Elephas maximus borneensis

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Once believed to be remnants of a domesticated herd given to the Sultan of Sulu in the 17th century, pygmy elephants were determined by WWF to be genetically different from other Asian elephants. DNA evidence proved these

elephants were isolated about 300,000 years ago from their cousins on mainland Asia and Sumatra. Over time, they became smaller with relatively larger ears, longer tails and straighter tusks. Today, the pygmy elephants of Borneo are the smallest elephants in Asia.

The Bornean orangutan differs in appearance from the Sumatran orangutan, with a broader face and shorter beard and also slightly darker in color. Three subspecies are recognized, each localized to different parts of the island:

 Northwest Bornean orangutans are the most threatened subspecies. Its habitat has been seriously affected by logging and hunting, and a mere 1,500 individuals or so remain. Many habitat patches in the area are small and fragmented.

 Northeast Bornean orangutans are the smallest in size and found in Sabah and eastern Kalimantan as far as the Mahakam River.

Wild bonobos can only be found in forests south of the Congo River in the Democratic Republic of Congo (DRC). Sometimes known as the pygmy chimpanzee, bonobos weren’t recognized as a separate species until 1929. As the last great ape to be scientifically described, much remains unknown about the bonobo—including the extent of its geographic range. Efforts to survey the species over the past two decades have been hampered by the remote nature of its habitat, the patchiness of their distribution and years of civil unrest within the DRC.

Chimpanzee Pan troglodytes

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Eastern Lowland Gorilla Gorilla beringei graueri

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Fin Whale

Balaenoptera physalus

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Throughout the unrest, the gorillas have been vulnerable to poaching, even in Kahuzi-Biega National Park, home to the largest population of protected eastern lowland gorillas. Rebels and poachers invaded the park and people set up illegal mines. But, with help from WWF and other

organizations, park staff are reestablishing control over the land.

In their habitat in the forests of central Africa, chimpanzees spend most of their days in the tree tops. When they do

come down to earth, chimps usually travel on all fours, though they can walk on their legs like humans for as far as

a mile. They use sticks to fish termites out of mounds and bunches of leaves to sop up drinking water.

Galápagos Penguin Spheniscus mendiculus

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Ganges River Dolphin Platanista gangetica gangetica

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Green Turtle Chelonia mydas

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Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Indian Elephant Elephas maximus indicus

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Indochinese Tiger Panthera tigris corbetti

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Indus River Dolphin Platanista minor

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Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Loggerhead Turtle Caretta caretta

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Malayan Tiger Panthera tigris jacksoni

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North Atlantic Right Whale Eubalaena glacialis

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Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Orangutan

Pongo abelii, Pongo pygmaeus

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Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Snow Leopard Panthera uncia

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Sri Lankan Elephant Elephas maximus maximus

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Tiger

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Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

Leatherback turtles are named for their shell, which is leather-like rather than hard, like other turtles.They are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. Pacific

leatherbacks migrate from nesting beaches in the Coral Triangle all the way to the California coast to feed on the abundant jellyfish every summer and fall.Although their distribution is wide, numbers of leatherback turtles have seriously declined during the last century as a result of intense egg collection and fisheries bycatch.

PAPER 5 NOTES

Hey,

Erm so I was looking up threads that might actually help in Paper 5 [considering I have my mock exam tomorrow] but I couldn't really find one, so decided to post one.

Things You Should Know For: Design, Analysis and Planning VARIABLES

Scientists use an experiment to search for cause and effect relationships in nature. In other words, they design an experiment so that changes to one thing causes something else to vary in a way that the scientist can describe as a 'trend'. The most useful way to describe a trend is a mathematical one. These changing quantities are called variables, and an experiment usually has three main kinds: independent, dependent, and controlled.

*The independent variable is the one that is changed by the scientist. In an experiment there is only one independent variable. This is usually plotted on the X-axis of the graph that the scientist uses to display his/her results in.

As the scientist changes the independent variable, he or she observes what happens.

*The dependent variable changes in response to the change the scientist makes to the independent variable. The new value of the dependent variable is caused by and depends on the value of the independent variable. For example, if you turn on a water tap (the independent variable), the quantity of water flowing (dependent variable) changes in response - the water flow increases. The more open the tap - the faster the flow of water. The number of dependent variables in an experiment varies, and there is often more than one.

*Experiments also have controlled variables. Controlled variables are things that would have an effect on the dependent variable. S/he must be sure that the only thing affecting that variable is his/her adjustment to the independent variable.

So, controlled variables are quantities that a scientist needs to keep constant, and s/he must observe them as carefully as the dependent variables.

For example, if we want to measure how much water flow increases when we switch on a tap, it is important to make sure that the water pressure from the water supply (the controlled variable) is held constant. That's because both the water pressure and the opening of the tap valve have an impact on how much water flows. If we change both of them at the same time, we can't be sure how much of the change in water flow is because of the faucet opening and how much because of the water pressure. Most experiments have more than one controlled variable. Some people refer to controlled variables as "constant variables."

Whenever you design an experiment you have to first 'set the scene'.

You are not ever finding anything out without any preconceptions. You always have ideas about what you are going to find out - you have expectations!

In a science experiment these expectations will be based on: - what you have experienced in life,

-experiments you have carried out before and

-scientific knowledge (things you have been taught about science at school, or have found out from books).

*In your report you need to explain to the reader what you expect to find out and why!

*You do not have to look into a crystal ball and write down numeric predictions... just predict a general trend. A good way to do this is to sketch a graph!

*You do have to explain the main scientific ideas that your prediction is based on. Try to use scientific

keywords in this section and explain in simple terms what you understand them to mean. A Fair Test

A fair test situation is vital for an investigation's results to be meaningful. You therefore have to use the scientific knowledge you have explained toidentify the variables in your investigation - things you have to control, otherwise it will not be a fair test. Say what will need to be controlled and why - using theory to explain it.

One of the variables will be the variable you are going to change. Say which on you are going to change and by how much (the range over which you will change it). Say how you found out that was a suitable range. It may well be your preliminaries that helped you decide on a suitable range! Then say have you are going to control all of the others you have identified.

Your fair test must be linked to your scientific knowledge.

*PRELIMINARY READINGS

You will have a rough idea of what you want to do, but will need to 'tweak' your idea by trying things out practically. You therefore sketch out a rough experimental procedure and test out the best way to do it in a preliminary session.You may want to:

- choose materials to work with: check that you will get a big enough range of readings with the ones you have chosen to investigate.

- find out if you are controlling the other variables well enough to have a 'fair test'.... maybe you will spot some you hadn't thought of!

- practise using the equipment, and see if you need to make adjustments to avoid or minimize errors.... or make it safer!

- spot dangers in your procedure that you ought to avoid.

Always check with a teacher before you carry out preliminary experiments - they have more experience at spotting potential dangers than you do!!

What you find out from your preliminary readings will influence your final design of your experiment. Remember to say in your report if you found out a better way to do it from preliminary work.... and how you checked your ideas were sound before proceeding.

*PROCEDURE

The procedure has several parts to it:

*A fully labelled diagram of the experimental equipment.

This should be so detailed that a person could carry out the experiment just from the diagram! It must be fully labelled with specifications of the equipment (e.g. '250 ml beaker' rather than just 'beaker'). Measuring instruments must have their range as well as increments marked on them (e.g. rather than 'thermometer' you would put a mercury filled thermometer with a range of -10oC to 110oC in 0.5 oC increments) A full side of A4 should be given to this!

*A full list of equipment - including minor parts

This should be done on a separate sheet of paper as a list to be given to a technician. Full specifications of the equipment (e.g. '250 ml beaker' rather than just 'beaker') must be requested. Measuring

instruments must have their range as well as increments marked on them (e.g. rather than

'thermometer' you would put a mercury filled thermometer with a range of -10oC to 110oC in 0.5 oC increments). Odds and ends such as: 4 connecting wires, 2 crocodile clips, sellotape etc. must be itemized.

*A risk assessment

List all of the possible hazards you have identified and how you intend to avoid them.

*A set of instructions

These should be in past impersonal tense.... 'The apparatus was set up as shown in the diagram. The beaker was filled with 100 ml water... etc.'. This is far better than a list of instructions with bullet points - but you may want to start off with such a list and then translate it into the correct form of English for scientific writing. The order must be logical!Don't forget to say that the experiment was repeated, how many times it was repeated etc. Remember to say that results were recorded - in a table of whatever, averaged, and that a graph was plotted.

*RESULTS/ANALYSIS

When successive measurements of the same quantity are repeated there is a distribution of values obtained. In experimental physics it is vital to be able to measure and quantify this uncertainty. The words "error" and "uncertainty" are often used interchangeably by physicists - this is not ideal - but get used to it!

Some important questions can only be answered if, in addition to performing an experiment, an error analysis has been conducted. These include:

 Are they reproducible?

 Has a new phenomenon or effect been observed?

*Types of Error

We need to identify the following types of errors:

 Systematic errors - these influence the accuracy of a result  Random errors - these influence precision

 Mistakes - bad data points.

*Accuracy and Precision

These are two terms that have very different meanings in experimental physics. We need to be able to distinguish between an accurate measurement and a precise measurement. An accurate measurement is one in which the results of the experiment are in agreement with the ‘accepted’ value. Note this only applies to experiments where this is the goal – measuring the speed of light, for example. A precise measurement is one that we can make to a large number of decimal places.

*ERRORS

These cause reading to be different from the true value. For example; Error is a measure of how close you can be sure about your measurement.

Percentage error = (smallest measurement you can measure/your measurement)*100 e.g. a ruler in mm divisions measure

es a length of 10 mm. The smallest

that the ruler can measure is to within 0.5 mm. So the error in my measurement of 10mm is;

(0.5 mm/10 mm ) x 100 = 5%

This means I have measured 10 mm +/- 5%

The measurement may actually have been as big as 10.5 mm or as small as 9.5 mm.

*Types of Errors - Random

Random errors may be detected and compensated for by taking a large number of readings. For example: Random errors may be caused by human error, a faulty technique in taking the

measurements, or by faulty equipment. These cause readings to be spread about some value other than the true value; in other words, all the readings are shifted one way or the other way from the true value.

- Systematic

readings are shifted one way or the other way from the true value.

- Zero

For example: A zero error occurs when a needle on an ammeter fails to return to zero when no current flows, or when a top-pan balance shows a reading when there is nothing placed on the top-pan balance

now x is suppose.. 83 +/- 5...

You can work either with upper limit and mean value (88 and 83) OR

You can work with mean value and lower limit (83 and 78) I will go with the former (88 and 83)

the uncertainty is = lg 88 - lg83 = lg (88 / 83) = 0.025 If I work with mean value and lower limit (83 and 78) the uncertainty is = lg 83 - lg78 = lg (83 / 78) = 0.025 So, the final answer is

log(83 +/- 5) = 1.92 +/- 0.025

Yes my teacher told me and i also saw this in the book of which i have posted snapshots

= [log(UL) - log (LL)]/2

^This is also correct!

We can further modify it using a little knowledge of logarithms and it becomes = 0.5 lg (UL / LL)

EXPEMPLE

QUESTION

Hey could someone tell me to find the absolute error of a log eg. 1.2+/- 0.1 can i do it like this [(0.1)/(1.2)] * [log(1.2)]? Or is this wrong?

And if if there is no log it would just be.... (0.1/1.2) * 100 right? Its from october november 2007

ANWER

If a function such as log or ln is used to calculate the values, then for e.g value is 6.0 +/- 0.5, to find error: absolute error = log (6.0+o.5) - log 6.0

OTHER

Sweet thanks, i was reading other threads too, thats the same as doing this:

(Log(6.5)-log(5.5))/2 and also log(6.5/6.0) right? Even though the answers are slightly different? Oh and also is absolute error the same as absolute uncertainty?

ANSWER

Yes, you can do either of these 3 to get the answer. However I prefer the way I showed you, more simple and less chance of making a mistake while typing in values on the calculator.

associated with an estimate whose true value is not known. Error is a quantity that is associated with an estimate whose true/accepted value is known.

But for our A-level papers, they tend to mean the same thing

some uncertainties help note

# equals change

1.when finding error for logs log(worst value) - log(best value) 2. when square #x^2/x^2 = 2(#x/x) 3. when in formula say-> Y= x/z so error=> #y/y= #x/x + #z/z

4. when finding gradient

diff of best gradient and worst gradient 5. when y-intercept errors

find y-intercept with bst gradient than with worst gradient find their diff that is your uncertainity mostly same is the case with the last one

here's a revision note for 9702 physics paper Question 1:

first be able to reduce the equation in the simplest form ..i.e y=mX=c ..and recognize the gradient calculate the data in 3 s.f(generally done) or to one s.f more or equal to the s.f of the raw data

in case of logarithmic calculations, the number of d.p is the number of s.f ..hence for a raw data of 3 s.f the log should be calculated to 3 or 4 d.p

to calculate absolute uncertainty the most accepted method is to calculate the maximum difference and divide by 2 ..sf of uncertainty is usually ignored in the mark scheme but stick to 1 or 2 s.f

plot all the six points,a small encircled dot is acceptable use sharp pencil to plot , and draw the error bars. all to nearest half square on the grid.

(u can also analyze from the graph as how much s.f to use..as the graphs interval's points's tenth division place is to be plotted )

the gradient should be calculated by drawing a triangle and mentioning the points of the vertices in the best-fit line ..the hypotenuse should be greater than halt the length of the best-fit line.

working should be shown clearly

and the worst-fit line is drawn by joining the top of the topmost point's error bar and the bottom of the bottommost error bar..and the line should touch every error bar.

both line should be clearly LABELLED ,and the gradient of worst-fit is calculated in similar way to best-fit ..calculate it on the blank page at the end..and just show the gradient value in working area while calculating the uncertainty in gradient..

the error in gradient is gradient of best fit - gradient of worst fit ,or 1/2 * (steepest line's gradient - shallowest line's gradient)

all calculation to 3 s.f

and for calculations , which is usually related to the calculated gradient, take care of units, power of tens and to calculate the percentage uncertainty work out the value with the gradient and again with the error+the gradient and work out the difference which is the absolute uncertainty , hence calculate the percentage uncertainty .(working is only credited here and calculations are not checked)

Question 2:

state the basic statement, it is awarded 1 mark..such as change pressure and measure power..and repeat(o/n 05)

Draw a diagram with all the equipment you might use during the experimentation of this plan..a basic, well labelled diagram could score many marks; even if the explanation is weak.

make sure you know the working of some equipments as:

collimator,sonometer, strobe, bourdon gauge, joule meter,thermometers,light-spot galvanometer needle valve, vacuum grease , lightgate, smart pulley ,balance,newton meter,ticker tape data-loggers , optical bench, set squares etc.. don't panic of you don't but u should know what equipment to use to measure something.

make sure u understand the question and collect all the method marks by suggesting means of measuring the quantities u might measure during the experiment.

there are 5 method marks to be scored.

now beware of safety measures. like earmuffs eardrums, goggles , safety screens . sand bucket for falling masses..etc

now be able to point some additional details they are worth 4 marks. these can also be awarded on a detailed diagram..

suggest the possible ranges of devices, suggest some ways of sophisticating the experiment..but donot make vague references and do not forget why are u performing this experiment .

Btw, i feel the method i used is easier as you just have to find the UL and not both UL and LL My formula:

= lg (UL / RL)

*RL means real value

Experiments that have been asked to be designed so far:

angelicsuccubus said: ↑

1. investigating the terminal velocity of a steel ball dropped in oil and it's relation to the radius 2. determining the resistivity of glass

3. determining the Young modulus of wood

4. investigating the relation between the depth of a nail being hammered into wood and the speed with which it's hammered (jobless much?)

5. determining the absorbtion coefficient of glass

6. investigating the relation between the amplitude of a sound wave and the air pressure inside a double-glazed window

7. investigating the relation between the resistance of an LDR with the distance from the light source

8. investigating the relation the volume of air in a bottle and its resonant frequency 9. investigating how the emf in a coil Y depends on the frequency of the current in coil X

10. investigating the relation between the strength of the magnetic field and the radius of the coil, using a hall probe

I didn't go through all the variants so someone else can add to the list.

ANSWER

Okay so im gonna try and see what we can do to solve these,people please correct/add to this!!

1 - Measure time for each ball of different radius and put in some equation. (Which one??!) 2- R=(rho)L/A - Vary length of the glass.

3- Stress/strain. (I dont know how to go about this) 4-

5- I have NO idea. What formula do we use? 6- Idk

7- Yes! this is fairly simple. R is inversely proportional to the intensity of light

8- Try different volumes,and the loudest heard sound will correspond to that particular volume ? 9- Vary current,see what effect that has on the emf.

10- No idea!! :/

You always need both an independent and dependent variable. Use the equation, and re-arrange it to find what can be easily varied and measured.

Independent variable =IV dependent variable =DV

1.IV = radius, DV= terminal velocity (use light gates to measure time taken to fall fixed distance to find terminal velocity)

2. IV = length or are, DV = resistance

3. IV = weight of the load, DV =extension produced. (other quantities kept constant)

4. IV= speed of nail(light gates connected to timer will measure time taken to fall fixed distance,and hence speed), DV =depth of nail into wood (use vernier)

5. you're given an equation for this. Re-arrange it to see what can be made the IV.

6. Use loudspeaker connected to a.f signal generator, microphone to C.R.O, and bottle to which vacuum pump and pressure gauge attached.

Guys this is an answer to qs 1 of j07. I want to know the correct way of writing the answer. I have posted my answer to question 1 below. If there are any problems with my answer please tell me so that i can correct my answer. Thanku in advance.

In this experiment the independent variable is r and the dependant variable is v, the terminal velocity of the object. A constant variable in this experiment is temperature. Another constant variable is the distance when time is being measured.

We will calculate the diameter of the ball by using vernier calipers and then we will calculate the radius by using the formula d=r/2. We take metal balls of different radii to vary r. We measure the time taken for the ball to fall a fixed distance through the oil. To ensure the ball falls through a fixed distance we place fudicial markers on the container. We will measure the time taken for the ball to fall through two fixed points of the container at terminal velocity. Then we will calculate the terminal velocity of the ball by using the formula v=s/t. We will take multiple trials for each ball and then take out the average speed to reduce random errors in the experiment.

To ensure the ball has reached terminal velocity we will place fiducial marks well below the surface of the oil. We will take the diameter of the ball at different points of the ball and calculate the average. The oil used in the experiment should be clear and the container should be wide and transparent.

After calculating all the required values will plot a graph of v against r2. If the graph has a straight line passing through the origin then relationship has been confirmed. One safety precaution is to prevent the oil ffrom being near any fire because it may be flammable.

im sry i didnt see that ur a girl....sry...one more thing so when do we use the formula

[{value+uncertainity} - {value-uncertainity}]/2 AND when should we use the fractional formula??? kind of confused with that....

i's alright

use the first one for logs and the second one when value is to be calculated either from division or multiplication, eg when R (resistance) is to be calulated from voltage V and current I, then R will be found out by V/I and uncertainity by adding their fractional errors and then multiplying by the R u got previously with their values...

let me brief u on errors : 1-ADDITION OR SUBTRACTION :

when 2 measurements are added or subtracted their errors are ALWAYS added up eg :

when u wanna add 2 +/- 0.2 and 3 +/- 0.2 then ure final answer shud be 6 +/- 0.4...if u r asked to find the percentage error frm this then find fractional error and multiply with 100 like 0.4/6 = 0.06667 now multiply with 100 = 6.67%

2-PRODUCT :

(product of values) +/- (sum of fractional errors)(product of values)

eg for multiplying 5 +/- 2 with 10 +/- 2...after applying above formula ure answer shud come out to be 50 +/- 30

3-DIVISION :

(division of values) +/- (addition of fractional errors)(divsion of values)

eg for dividing 5 +/- 2 with 10 +/- 2...after applying above formula ure answer shud come out to be 0.5 +/- 0.5

4-CONSTANT POWER

(powered value) +/- (power x fractional error)(powered value) eg if U = 4 +/- 0.2....find out U^2 then :

(4^2) +/- (2 x 0.2/4)(4^2)---> 16 +/- 1.6

yeah i have problem understanding what are light gates and when to use them in experiments. And can u also explain about the electromagnet switch u were talking abt?

light gates measure timings for a object to fall a particular distance..u have a light source on one end and a timer on the opposite, when a ball falls between them the light gets obstructed and the sensor on the other side no longer detects any light ( at this time ball is right infront of the timer), the timer

starts,,,,having another such thing below this set up at a fixed distance h starts this second timer and the difference in readings from the first and second will be the time measured but u dont need to explain all of this in the procedure just say measure timings through light gates

for an electromagnet u OPEN the switch nd electromagnet no longer retains its magnetism letting go of ball..

im attaching a file, but remember in this case the ball is to be dropped from surface of oil to avoid a splash (a safety)

a simple setup is in oct 2009 paper 52

can you show the pic of worst acceptable line joining error bars? plz

Its does look great but gives a rough idea that the worst acceptable line should start for the lowest point of the first error bar to the top of the highest error bar.

why 1.5?

i thought 0.5 above 2.5 and 0.5 below 2.5.

The value of current was 2A, and the error is plus/minus 0.5

so, you add 0.5 to 2 , to get the upper limit of the error bar, and you subtract 0.5 to get the lower limit of the error bar

hence, 2+0.5 = 2.5 (upper limit) and 2 - 0.5 = 1.5 (lower limit)

Hi, so what are the basic strategies to score full marks for question 1? This is what I've got in mind so far:

- 3 variables (independent, dependent, constant) - Draw and label a diagram

- Method for carrying out the experiment (briefly explain how the experiment is carried out, vary the independent variables, record the data, plot a graph)

- Draw a graph and label it (if an equation is given use it to find the x/y axis and the y-intercept and outline how the gradient is calculated)

- Describe at least 5 safety precautions/additional information Anything else to add on?

Paper 5 Tips: Practical Test

Planning Question

• Do not panic if the context of the question appears unfamiliar to you. During your A Level studies you will have used or learnt about suitable apparatus for completing the task. If you are asked to ‘use’ any unfamiliar apparatus the question will supply you with all the details that you need to know about. • Read the question very carefully – it may give you guidance on those aspects of your plan to which you need to pay particular attention. It will also help you to identify the independent and the dependent variables.

• When writing your answer you will need to consider some or all of the following: - what apparatus you will use

- what experimental arrangement will be used - what procedure will be followed

- the independent and dependent variables

- the means of keeping other variables constant - use the word ‘constant’ when identifying these variables, saying you will ‘control’ them is insufficient

- how the raw data readings will be processed to give the desired result, e.g. what derived quantities you might calculate or what graph you might plot

- what relevant safety precautions should be in place

• The relationship to be tested, given to you in the introduction to the task, will suggest the type of graph to be expected. You will need to describe it as

precisely as possible. For example, is it linear, does it pass through the origin? If you choose a logarithmic graph, you will be expected to predict its slope from the

given expression.

• When writing your answer you must write down all the information clearly and explicitly - the examiner cannot give you marks for things that are vaguely implied.

• Many of the marks can often be scored by having a good working diagram (even if the accompanying explanation is weak) and so you should spend time making sure that your diagram shows all the relevant details and is fully labelled. For example, make clear the exact points, between which, measurements, such as distance, are to be made.

• The equipment and procedures that you describe in your answer should be realistic and workable. • One mark is available for describing safe working. This must relate specifically to the apparatus being used. It is not sufficient to write, for example, ‘keep all bags and coats out of the way’.

• Additional marks are available for detailed descriptions of apparatus/techniques. There are always more possible answers than marks available, so if you write your plan carefully, then some these marks should be gained as you go along. It is not expected that you write a separate section solely for the detail marks.

• As part of your preparation for this question you should plan some of your own experiments, but this should be done under the close supervision of your teacher. Also practise answering past papers.

• A sketch graph is not necessary, but if drawn it should be consistent with your description of the graph. Evaluating data Question

• The number of significant figures used in a derived quantity that you calculate from your raw readings should be equal in number to (or possibly one more than) the number of significant figures in the raw readings. For example, if you measure potential difference and current to 2 and 3 sig figs respectively, then the corresponding value of resistance calculated from them should be given to 2 or 3 sig figs, but not 1 or 4. If both were measured to 3 significant figures, then the resistance could be given to 3 (or 4) sig figs.

• When drawing your graph, do not forget to label each axis with the appropriate quantity and unit, using the same format for expressing column headings in a table. Choose a scale such that the plotted points occupy at least half the graph grid in both the x and y directions. The x-axis scale should increase positively to the right and the y-axis scale should increase positively upwards. Use a convenient scale such as 1, 2 or 5 units to a 2cm square as you will then be less likely to make a mistake with the position of your plotted points and it will be easier for you to read off points from your graph if you are

calculating the gradient or finding an intercept. Similarly, it is good practice to mark values on at least every other 2cm square.

• All your plotted points should be on the grid; points in the white margin area will be ignored. Plot all your observations and ensure that they are accurate to half a small square. A fine cross (or an encircled dot) drawn with a sharp pencil is acceptable, but be careful not to obscure the position of your points by your line of best fit or other working.

• When drawing your line of best fit, ensure you have an even balance of points about the line along its whole length. If it is a straight line, use a clear plastic rule so that you can see points on both sides of the line as it is being drawn.

• Show all your working when calculating a gradient. It is helpful to draw the triangle used to calculate the gradient on the graph and to clearly label the coordinates of the vertices (accurate to half a small

square). These values can then be used in the gradient calculation. The length of the hypotenuse of the triangle should be greater than half the length of the graph line.

• If you are required to give a value for the y-intercept, it may be possible to directly read it off from your graph from an axis where x=0. If this is not possible you can instead calculate the y-intercept by using the equation of a straight line. In this case you should substitute into this equation a pair of x and y values from your line of best fit along with your calculated value of gradient.

• It is particularly important that the rules, previously given for significant figures, are strictly adhered to. • You will be expected to use the uncertainty given in the raw data to find the uncertainty in calculated data. The latter will involve a function such as a logarithm. This requires plenty of practise, if you are to be able do it with confidence in the examination.

• You will need to be able to translate the calculated uncertainties into error bars on your graph and then to draw the worst acceptable line. Again, this requires plenty of practise.

• Once the graph has been drawn, you will be expected to find uncertainties in both the gradient and the intercept – using your line of best fit and your worst acceptable line. A lot of marks depend on your being able to calculate the uncertainties in the calculated data.

• Every candidate is provided with the same data and so the final values calculated should be very similar. One mark is available to candidates who manage to work within a given tolerance, determined by the Principal Examiner.

Source:Learner Guide for Cambridge AS and A Level Physics(© Cambridge International Examinations 2012)

Hope this helps!!!

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_52.pdf

How to do the errors part here ?> errors in log T ?

Soldier313 fb.junks

or anyone ?

for this one ...calculate the error in T values which o.2/10 = 0.02

now get the upper limit of T which is for the first one in the table lg(1.96+0.02) subtract this from normal lg value ...which is lg1.96

so lg1.98-lg1.96 = 0.004 easy peasy and so on

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_52.pdf

How to do the errors part here ?> errors in log T ?

Soldier313 fb.junks

or anyone ?

{x + delta x/2 } / { x - delta x /2} take log of whole term ...like for first box ... {1.96 + (0.2/1o)/2} / { 1.96- (0.2 / 10)/2} then take log

rafay malik said: ↑

Is it acceptable to write the answer to question one in bullet forms, under the specific headings? ( defining the problem, methods of data collection etc).

I am not sure but if it was even acceptable.The examiner will mark those points under only that specific heading only so I recommend to write in paragraphs with no headings so each point where ever

mentioned is considered.

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_53.pdf

Q2 e part please

V=V0e^-t/CR

.10Vo=V0e^-t/CR(AS 10% of original potential difference) ln(.10)=-15/CR (V0 eliminated on both sides)

Uncertainty of R=(Uncertainty of C/C )xR

Assalamoalaikum

can anyone plz tell me how to find the absolute uncertainties in Q2b

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s10_qp_51.pdf

Xc = V0 / I0

So, (Error in Xc) / Xc = [ (Error in V0) / V0 ] + [ (Error in I0) / I0 ] eg for first row:

Error in Xc = { [ 0.2/5 ] + [ (0.2x10^-3) / (15 x 10^-3) ] } x 330 Error in Xc = 18

Hope that helped Javior said: ↑

does anyone know how to draw a hall probe .. should we show the plane and voltmeter or just a probe labelled hall probe?

and is it true that if you attach a signal generator to a coil you an ac current? plz anyone ill be real grateful

...Just draw a box(label it with hall probe) and show connections to voltmeter and power supply ...or if u good at showing plane show the pplane perpendicular to field to get max voltmeter reading...and for second its true signal generator can produce ac...and we can vary frequency of ac..

Can someone please show me how to calculate the tabular values of v^2 ?

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w12_qp_53.pdf

v = s/t where s=distance, t=time v^2 = (s/t)^2

so v^2 = (0.05/t)^2

then substitute values of time from each row into the eqn eg for row 1, v^2 = (0.05/0.046)^2

so v^2 = 1.18

then uncertainty is (max value of v^2 - min value of v^2) / 2 so max value of v^2 = (0.051/minimum time)^2

subtract these two values and then divide by 2 to obtain uncertainty

Hope that helped

an anyone plz tell how the newtonmeter is used in finding the force b/w two charged plates in winter 2006 paper 5 question2?are there any weights added?plz explain IT'S URGENT!!

Can someone please show me the diagram for question #1 ?

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w09_qp_52.pdf

sorry you're seeing a reply after so long! Anyway i cant post a pic,but the basics of the diagram are what is shown in the question,plus:

-a meter rule placed vertically "behind" the wire,to measure distance -micrometer to measure diameter of wire

-rheostat in circuit to keep current constant and ammeter in current

thats it! hope i helped!

Aoa wr wb

Can someone please provide a detailed diagram and explanation for qn 1 of this paper please?

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w11_qp_51.pdf

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w11_ms_51.pdf

I'll try to upload an image later, but hopefully, for now, the explanation is okay - sorry!

The independent variable in the investigation is the field strength B at the center of the coil and the dependent variable is, then, the radius of the coil. Since the strength of the magnetic field at the center of the coil depends upon the current in the coil and the number of turns in the coil, these two variables need to be kept constant; no matter what the radius is, the same number of turns should be used (the more the coils, the greater the field strength, so it is a control variable) per coil. The current can be kept constant by placing a rheostat in series with the coil and using an ammeter to measure the current through the coil. If the current decreases, the resistance of the rheostat can be decreased to bring up the current. If the current increases (sudden surge, any other reason) the resistance of the Rheostat can be increased to bring the current down.

The experiment can be carried out by first taking a length of wire and wrapping it firmly around a cylindrical object; this will give it a coil-like shape with an approximately constant radius. To increase the radius later, a wider cylinder can be used. A ruler can be used to measure the diameter of the coil, and the result divided by 2 to get the radius. This measurement can be repeated around the coil along several diameters and the values of r averaged.

The coil can be connected to a d.c. power source, an ammeter and a rheostat, all in series (diagram) and the coil can be hung (after being flattened) from a clamp/ retort stand holder. The center of the coil can be found using a ruler, and a stack of books with a track/ruler placed on top of them can be aligned with the coil such that the ruler is perpendicular to the plane of the coil and is going into the plane of the coil. This track can be used to move the hall probe towards the center of the coil. The Hall probe should be connected to a calibrated galvanometer/ voltmeter, and the maximum reading shown can be noted down as the value of B. Several readings of B can be taken for each radius r and averaged to plot into the graph.

About 10 readings can be plotted into a graph of B on the y-axis versus (1/r) on the x-axis. If the relationship is indeed true, the graph should be a straight line through the origin (the equation is the form of B = k/r where k is a constant, so the gradient is B * r = k, so gradient is constant).

The coil may heat up due to the current passing through it, so it is advisable to let the coil cool down between experiment before replacing it/ using heat resistant gloves while doing so.

A large current can be used to ensure a large value of B; this reduces percentage uncertainties (any that might creep into the readings) and also gives a large value of B. Similarly, a large number of coils can also be used, but kept constant throughout the experiment. Any external currents and magnetic fields will have to be eliminated, so the experiment should be performed in an isolated location. Again, the current can be kept constant using a rheostat (as mentioned above) and if the same Hall Probe setup is being used for all the experiments, the probe and voltmeter can be calibrated in a magnetic field of known strength.

Hope this helped!

Good Luck for all your exams!

when we divide quantity by something.what will be the uncertainty of new value? mj/10/52 question number two.plz someone help

If you are referring to dividing t by 10 to give T, the uncertainty is also divided by 10.

The reason is that when you multiply/divide two quantities together, you add their percentage uncertainties to find the percentage uncertainty in the resulting value.

In this case, if you want to find the percentage uncertainty in the value of T, it will be the (% uncertainty in t) + (% uncertainty in 10) = (% uncertainty in t), since 10 is a constant, absolute value which is

completely accurate and has no percentage error.

As an example, if we take the first value of t, 18.9, the percentage uncertainty is: 0.1/18.9 = 0.00529 (0.5 %).

Therefore, the uncertainty in the final answer is 0.5% = 0.00529: The absolute uncertainty is 1.89 * 0.00529 = 0.01.

You can see that the uncertainty in 1.89 is 10 times less than the uncertainty in 18.9, so the uncertainty has been divided by 10, the same value that divided t to give T.

Hope this helped!

Good Luck for all your exams!

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_52.pdf

anyone did the graph portion ov this one? and the errors one too obviously ? can anybody show the graph plotted or the errors ?

Hopefully this diagram can assist you with the hall probe issue:

Question 1 of this paper

There's a bell jar with a bell inside it, If it already has a bell inside it, why do we need to provide a source of sound in form of a loudspeaker etc??!

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_nos_sp_5.pdf

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_nos_sm_5.pdf

You don't need to 'provide' a source of a sound in the form a loudspeaker. The bell is a source of sound, and that's more than enough.

A loudspeaker can be used as an additional material to make it easier for the person to hear the sound of the bell.

so mic is out side bell jar or inside it ???

"Workable arrangement Should include container, source of sound, pump, microphone, CRO"

Since this marking point is one of the methods of data collection rather than just an additional detail, it led me to assume that, we need a sound source.

So the bell is a sound source, no? Yeah it is.

But in the variables to be controlled it also states frequency of sound source, so how do we exactly control the frequency of the bell sound ?

MJ2008 MJ2010 51 MJ2011 52

Studen12345 said: ↑

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w12_qp_53.pdf

how to find uncertanity in v^2 in Q2 plzz answer tahnks

Ashrith said: ↑

Can someone tell me how to do the table for Q2 of 9702/53/O/N/12?

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w12_qp_53.pdf

v = s/t where s=distance, t=time v^2 = (s/t)^2

so v^2 = (0.05/t)^2

then substitute values of time from each row into the eqn eg for row 1, v^2 = (0.05/0.046)^2

so v^2 = 1.18

then uncertainty is (max value of v^2 - min value of v^2) / 2 so max value of v^2 = (0.051/minimum time)^2

min value of v^2 = (0.049/ max time ) ^2

subtract these two values and then divide by 2 to obtain uncertainty

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