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In This Issue

In This Issue

In This Issue

Editor

MAHENDRA JAIN

Editor/Publisher is not responsible for views, data, figures etc. expressed in the articles by the authors.

—Editor

No part of this publication can be reproduced or transmitted in any form without the prior written permission from the publishers.

Edited, printed and published by Mahendra Jain for M/s. Pratiyogita Darpan, 2/11A, SwadeshiBima Nagar, AGRA–2 and printed by him at Pratiyogita Darpan Printing Unit, 5 & 6, Bye pass Road, Agra. Phone : 4053333, 2531101, 2530966 Fax

: (0562) 4031570, 4053330 E-mail : publisher@pdgroup.in Website : www.pdgroup.in Branch Office : 4845, Ansari Road,

Daryaganj, New Delhi–110 002 Phone : 23251844/66 September 2009 Year—12 Issue—139

C.S.V.

/

September

/

2009

/

797

Regulars

Editorial 799

Science and Technology 801

Latest General Knowledge 805

Inspiring Young Talent—

Selected in UP-CPMT-2009 (Rank 6)—Ratish Kumar Mishra 809

Science Tips 811

Physics

Sound-I : Wave Motion 814

Nuclear Physics-I : Radioactivity 822

Typical Model Paper 828

Typical Model Paper 834

Chemistry

Transition Elements : Elements of d-Block 842

Aromatic Nitro Compounds : Nitrobenzene 849

Typical Model Paper 856

Typical Model Paper 861

Zoology

Human Skeletal System 866

Sexually Transmitted Diseases (STD) 872

Typical Model Paper 876

Typical Model Paper 879

Typical Model Paper 882

Botany

Vegetative Parts of Plant Body 885

Fat (Lipid) Metabolism 890

Biogeochemical Cycle 893

Typical Model Paper 896

Typical Model Paper 899

Other

Other

Other

Other

Other Features

Features

Features

Features

Features

Assertion and Reason Type Questions 902

True or False 905

Do You Know ? 909

General Awareness 913

CSV Quiz Contest No. 136 916

Correct Solution and Prize Winners of CSV Quiz No. 133 919

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To Our Readers

FORTHCOMING COMPETITIVE EXAMS.

Dear Readers,

The September issue of your favourite magazine ‘Competition Science Vision’ is in your hands. To start a fresh session of PMTs, all efforts have been made to make this issue totally examination-oriented and useful for various future tests.

It is worth repeating at this stage that the opinions of toppers, other successful candidates and readers in general have uni-vocally decided that CSV is a valuable guide which stands unmatched in its field. Even experts have ranked it as second to none in its utility. The magazine will undoubtedly improve your performance and give an extra-edge over other competitors which is so essential for success.

We also remind you that success comes to those who earnestly work for it. It requires hardwork and devotion. Remember a few months of hard labour can land you in a meaningful and fabulous career. The undisputed guidance of CSV is always available to you. It will give you enormous force for your success.

Read CSV regularly and intelligently. It gives you the power to master your career and shape your destiny.

With best wishes for your success. Sincerely yours,

Mahendra Jain

(Editor)

2009

Jharkhand High School Teachers Exam. (Aug. 9) Central Bank of India Probationary Officer Examination (Aug. 16) IGNOU B.Ed. Entrance Exam., 2009 (Aug. 16) Delhi Fire Service, Fire Operator Exam. (Aug. 23 & 30) U.P. Trained Graduate Teachers Examination (Aug. 23 & 30) PNB Management Trainee Exam. (Aug. 30) UPSC National Defence Academy and Naval Academy

Examination (II), 2009 (Aug. 30)

Indian Army Religious Teachers Exam. (Aug. 30) Indian Air Force Airman Selection Test Group ‘Y’ Trade (Aug.)

Bank of India Clerk Exam. (Sept. 6)

SSC Central Police Organisation Sub-Inspectors Exam., 2009 (Sept. 6) EPFO Social Security Assistant Exam., 2009 (Sept. 6) Madhya Pradesh Civil Judge Preliminary Examination, 2009 (Sept. 6) Union Bank of India Rural Development Officers/Marketing

Officers Exam. (Sept. 6)

Chhattisgarh State Service (Mains) Examination, 2008 (Sept. 12 & 13) SBI Management Executives Exam. (Sept. 13) (Online Closing Date : 10 Aug., 2009)

Combined Defence Services Examination (II), 2009 (Sept. 13) U.P. Lecturer Examination (Sept. 14)

PNB Clerical Cadre Exam. (Sept. 20)

Delhi SSSB Trained Graduate Teachers (English,

Mathe-matics, Natural Science) Exam. (Sept. 27)

Bihar Telecom Technical Assistant Exam., 2008 (Oct. 4) Delhi SSSB Trained Graduate Teacher (Social Science) Exam. (Oct. 10) UPSC CPF Assistant Commandants Exam., 2009 (Oct. 11) Reserve Bank of India Officers Grade ‘B’ Examination (Oct. 11) (Closing Date : 24 Aug., 2009)

Delhi SSSB Trained Graduate Teachers (Sanskrit, Hindi, Urdu,

Punjabi) Exam. (Oct. 11)

The New India Assurance Company Ltd. Administrative

Officer Examination (Oct. 25)

(Closing Date : 17 Aug., 2009)

Madhya Pradesh Civil Judge (Main) Examination (Nov. 8) National Talent Search Exam., 2009 (For VIII Class Studying

Students) (Nov. 8)

(Closing Date : 31 Aug., 2009)

Madhya Pradesh National Means-cum-Merit Scholarship

Examination, 2009-10 (Nov. 8)

S.S.C. Auditors and Accountants Exam. (Indian Audit and

Account Deptt.) (Nov. 15)

(Closing Date : 21 Aug., 2009)

Madhya Pradesh State Service (Mains) Exam., 2008 (Nov. 16) Indian Economic Service/Indian Statistical Service

Examination, 2009 (Nov. 21)

Rajasthan State Eligibility Test (SET), 2009 (Nov. 22) Indian Air Force Airman Selection Test [Group ‘X’ (Technical)

Trades] (Nov.)

Rashtriya Military Schools Common Entrance Test (Class VI) (Dec. 20) (Closing Date : 10 Sept., 2009)

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much earlier. According to ISRO Chairman, Madhavan Nair, the star sensor’s failure was due to excessive radiation from the Sun. As the sensor could not be recovered at this stage, the remainder of the two-year mission will be completed using a gyroscope, an electro-mechanical device that was used in Indian Remote Sensing satellites.

Gyroscope, however, needs regular intervention to stabilise the orientation, and the ISRO’s ground station has begun weekly altitude corrections. With the failure of the two star sensors, the number of technical glitches, Chandrayaan has encoun-tered in its nine-month lunar orbit, stand at three—third being the failure of a Bus Management Unit, which has been replaced by a back-up unit.

The Rs. 400 crore satellite had also encountered problems of thermal heating. On one instance, in January 2009, the temperature within the spacecraft had risen to 80 degree celsius. The optional temperature for electronic packages and payloads is zero to 40° celsius.

Chandrayaan was launched on October 22, 2008 carrying 11 payloads (scientific equipments for experiments), including the moon impact probe that crash-landed on a designated location near the moon’s South Pole in November 2008.

From Computer Hacking

to Brain Hacking

Hackers, who can easily break into personal computers, are giving researchers sleepless nights as they fear that someday the human brain might get hacked as well.

In the past years, researchers have developed technology that makes it possible to use thoughts to operate a computer, maneuver a wheelchair or even use Twitter—all without lifting a finger. But as neural devices become more complicated— and go wireless—some scientists say the risks of ‘brain hacking’ should be taken seriously.

Neural devices are innovating at an extremely rapid rate and hold tremendous promise for the future. If we do not start paying attention to security, we are worried that we might find ourselves in 5 or 10 years saying we have made a big mistake.

Hackers tap into personal com-puters all the time—but what would happen if they focussed their nefarious energy on neural devices such as the deep brain simulators currrently used to treat parkinson and depression or electrode systems for controlling prosthetic limbs ?

Brain Storming : As neural devices go wireless, hackers might try to mani-pulate deep-brain stimulators or elec-trodesystems for controlling prosthetic limbs.

The next generation of implant-abledevicestocontrolprostheticlimbs will likely include wireless controls thatallowphysicianstoadjustremotely the settings on the machine. If neural engineers do not build in security features such as encryption and access control, an attacker could hijack the device and takeover robotic limb.

Process of Capturing Geothermal Energy

Somemightquestionwhy anyone would want to hack into someone else’s brain, but the experts say that there is a precedence for using PCs to cause neurological harm.

Digging Deeper for

Geothermal Energy

A new project financed by the Energy Department of U.S.A., aims to capture geothermal energy from hot bedrock. But the rock must be broken upto extract the heat and that process creates earthquakes.

For decades energy companies have been drilling into a sandstone-like rock, called graywacke that is heated by hot bedrock underneath. The new project will drill miles deeper into the felsite rock that intrudes into the gaywacke, causing the rock to shift and break—and generate earth-quakes.

Thestart-upcompanyrunning the project‘AltarockEnergy’,says that the small tremors are negligible, and that large quakes can be avoided by con-trolling the fractures and staying away from known faults.

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AWARDS/HONOURS

Gandhi Peace Award

The pro-democracy Myanmar leader and Nobel Laureate Aung San Suu Kyi was felicitated with Mahatma Gandhi International Award for Peace and Reconciliation on July 21, 2009 in Durban. The Award was bestowed by the South African-based Mahatma Gandhi Foundation. Burmese Prime Minister in exile received the Award on her behalf.

The Award is in recognition of her strong commitment to non-vio-lence, justice and peace.

Sports Awards 2008

Khel Ratna Award—Four-time

women’s boxing World champion, M. C. Mary Kom was chosen for the Rajiv Gandhi Khel Ratna Award for theyear2008onJuly 20, 2009 in New Delhi.

The awardees :

Rajiv Gandhi Khel Ratna Award : M. C. Mary Kom (boxing).

Arjuna Award : Mangal Singh

Champia (archery), Sinimole Paulose (athletics),SainaNehwal (badminton), Sarita Devi (boxing), Tania Sachdev (chess), Gautam Gambhir (cricket), Ignace Tirkey and Surinder Kaur (hockey), Pankaj Shirsat (kabaddi), Satish Joshi (rowing), Ronjan Sodhi (shooting), Poulomi Ghatak (table tennis), Yogeshwar Dutt (wrestling), Girdhari Lal Yadav (sailing) and V. Prabhu (wheelchair tennis).

Dronacharya Award : P. Gopi

Chand(badminton),Satpal(wrestling), J. Uday Kumar (kabaddi), Baldev Singh (hockey) and Jaidev Bisht (boxing).

Royal Medal (for C.N.R. Rao)—

Noted scientist, Dr. C.N.R. Rao, National Research Professor at the Jawahar Lal Nehru Centre for Advanced Scientific Research, Bangalore has been awarded the prestigious Royal Medal by the Royal Society, London for his contributions

to solid state and material chemistry. The medal is awarded by the Queen on recommendations of the Council of the Royal Society.

BOOKS

Readings in Indian Agriculture and Industry—Edited by K. L. Krishna and Uma Kapila (A collection

of essays written by noted economists providing insights into two vital sectors of Indian Economy).

Global Bollywood—Edited by Anandam P. Kavoori and Aswin Punathambekar (The book is a

collection of scholarly essays which examine the manner in which Hindi cinema has reframed relationship among geography, cultural production and cultural identities).

Accelerating Growth and Job Creation in South Asia—Ejaz Ghani and Sadiq Ahmed (A study of South

Asian political economy beyond the conventional discourse of market and state).

Archaeology in India—Gautam SenguptaandKaushikGangopadhyay

(The book deals with the glimpses of the methods and means adopted by the pioners in archaeology to unravel India’s past).

DAYS

August1—WorldBreast Feeding Day

August 3—International

Friend-ship Day.

August 6—Hiroshima Day. August8—WorldSeniorCitizens’ Day.

August 9—Quit India Day,

Nagasaki Day.

August 15—Independence Day

of India.

August 18—International Day of

the World’s Indigenous People.

August 19—Photography Day. August 20—Sadbhavna Diwas. August29—NationalSportsDay.

Gangubai Hangal—A doyenne

of Hindustani classical music and one of the foremost exponents of the Kirana Gharana, Gangubai Hangal passed away on July 21, 2009 in Hubli, Karnataka. She was 97.

A recipient of more than 50 awards, includig the Padma Vibhu-shan, the Padma Bhushan and the Central Sangeet Natak Akademi Award,fourhonorarydoctoraldegrees and 24 titles, Ms. Hangal had the rare honour of being felicitated by nine Prime Ministers and five Presidents.

Abdullah Bukhari—Former

Shahi Imam of Delhi’s Jama Masjid, Syed Abdullah Bukhari, died on July 7, 2009 following a heart attack. He was 87. He is survived by four sons and two daughters. He was the 12th Shahi Imam of the grand old mosque built by Mughal emperor, Shah Jahan. Born in Rajasthan, Syed Abdullah Bukhari completed senior cambridge and became Naib-Shahi Imam in 1946. He became Shahi Imam in 1973. He was one of the strong voices that opposed the Emergency in 1975. His eldest son is the current Shahi Imam.

Shiv Charan Mathur—Assom

Governor and former Rajasthan Chief Minister, Shiv Charan Mathur passed away in New Delhi. He was born on February 14, 1926 in Guna district of Madhya Pradesh. He shifted to his maternal grandfather to Karauli (Rajasthan). Twice he had been the Chief Minister of Rajasthan—since July 14, 1981 till February 23, 1985 and since January 20, 1988 till December 4, 1989.

R. S. McNamara (U.S. Defence Chief during Vietnam War)—Robert

S. McNamara, the cerebral Secretary of Defence of U.S.A. who was vilified for prosecuting the Vietnam war, died on July 6, 2009 in Washington. He was 93. He was fundamentally associated with the Vietnam war, America’s most disastrous venture.

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Known as a policymaker, McNamara was recruited to run the Pentagon by President John F. Kennedy in 1961. Later on, Mr. McNamara served as the President of World Bank for 12 years.

Pradeep Kumar (New Defence Secretary)—Union Government

appointedPradeepKumaras Defence Secretary on July 13. Mr. Kumar, a 1972 batchHaryanacadre IAS officer, had been working as Secretary (Defence Production). He succeeded Vijay Singh who retired. Mr. Kumar, who will be 60 years of age this September, will get a two-year tenure as per the decision taken by the governmet. He is a graduate in Electrical Engineering from IIT, Delhi.

Nirupama Rao (New Foreign Secretary)—Nirupama Rao took over

as the Secretary of External Affairs. She succeeded Shiv Shankar Menon who retired. Before this, she had been work-ing as Ambassador to China. A

1973-batch officer of the Nirupama Rao Indian Foreign Services, Ms. Rao has extensive experience of full range of diplomatic assignments that a pros-pective Foreign Secretary is expected to have. She worked as Indian High Commissioner to Sri Lanka, Ambas-sador to Peru and Deputy Head of Indian Embassies in Moscow and Washington. She will turn 60 in December 2010.

Indira Jaisingh (New Add. Solicitor-General)—Eminentlawyer of Supreme Court, Indira Jaisingh, is appointed as the first woman Additional Solicitor-General of India. She has also been a human rights activist.

VikasSwaroop—VikasSwaroop, whose book was turned into the Oscar-winning ‘Slumdog Millionaire’, is appointed as the India’s Consul-General in Osoka, Japan.

Hansraj Bhardwaj (New Gov., Karnataka)—Former Union Minister

for Law and Justice, Hansraj Bhar-dwaj was sworn-in as the Governor of Karnataka. Born in 1937 in Haryana,

Mr. Bhardwaj began his career as the Public Prosecutor for the Delhi Administration and Delhi High Court and rose as a Senior lawyer in Supreme Court.He has also authored three books.

Devanand Konwar (New Gov., Bihar)—President Pratibha Patil

appointed Devanand Konwar as the Governor of Bihar. Mr. Konwar had been Finance Minister of Assom.

Ramesh Pokhriyal (New CM, Uttarakhand)—Mr. Ramesh Pokhriyal

‘Nishank’ was sworn-in as the fifth Chief Minister of Uttarakhand. Mr. Pokhriyal (51) succeeded Mr. Bhuvan Chandra Khanduri, who had tendered his resignation.

G. K. Pillai (New Home tary)—The former Commerce

Secre-tary, Mr. Gopal Krishna Pillai, took over as the Union Home Secretary. Earlier Mr. Pillai had also served as the Joint Secretary in Union Home Ministry.

HillaryClinton—TheU.S. Secre-tary of State Hillary Clinton’s five-day visit to India was

meant to herald a new era in bilateral relations, the em-phasis she laid on theneed to conclude the end use moni-toring agreement

(EUMA) for the sale Hillary Clinton of American military hardware sug-gests that Washington is looking at its strategic partner in purely transac-tional terms. For this dialogue to be meaningful, Military and civil nuclear cooperation were key pillars of the bilateral talks.

Bandra-Worli Sea Link—A proud Landmark—With the

inaugu-ration of the picturesque Bandra-Worli sea link, more than four decades after it was first mooted, Mumbai’s land-scape has acquired an undeniable facelift. This is India’s largest sea link, the third of its kind after Pamban RailwayBridgeconnectingMandapam and the island of Rameshwaram and

the Indira Gandhi Bridge (built in 1988)thatrunsparallel to the Pamban Bridge. The 5·6 km Bandra-Worli sea link with its cable-stayed bridge is an impressiveengineeringfeat and struc-tural wonder in recent times.

This Rs. 1600 crore link has undoubtedly become the new icon of the city. The link is meant to be extended to connect Worli and Haji Ali in the next phase, enhancing mobility further within the heavily congested city. The highlight of this project is that it is designed for the vehicles to travel 100 km per hour, reducing the travel time from 40 minutes to seven and thus saving on the vehicle operating costs. It is promissing to note that the Bandra-Worli link, when it is fully operational, will have two of its eight lanes dedicated to buses.

Desert National Park (In UNESCO’s Heritage List)—After

remaining merely on official records for almost three decades, the ‘Desert National Park’ in Jodhpur division is nowontheTentativelistofUNESCO’s World Heritage. The unique habitat, a 3,162 sq. km, treeless, sandy, gravel and rocky tract punctuated by deso-late hills, houses many rare and endangeredspeciesoffloraand fauna including the Great Indian Bustard.

Unique Habitat : The Desert National Park is home to endangered species

like the Great Indian Bustard. The ‘Desert National Park’ accounts for 60 species of mammals, including chinkara desert fox, desert hare, hairy-footed gerbil and long-eared hedgehog. This park can take pride in the fact that it is home to Rajasthan’s state bird, the Great Indian Bustard,State tree khejri, State animal chinkara and the state flower rohida.

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15th Summit of Non-Aligned Movement (NAM)—Two-day summit

of Non-Aligned Movement was con-cluded at Sharm El-Sheikh in Egypt on July 16, 2009. In a concluding declaration, this 118-nation grouping ended their summit with an agenda that was both, focussed and compact, emphasising the need for collective action on the principal global issues of the day.

From disarmament and terrorism to climate change, the financial cricis and Palestine, there was virtually no global problem of relevance of the developing world that was ignored. Yet by spelling out a future agenda, the Non-Aligned Movement leaders have increased the likelihood of the summit declaration being taken seriously by its own members and rest of the world.

G-8 and G-5 Summits—Leaders

of the G-8 industrial nations and the G-5 developing countries started their summit in L’Aquila, a mountain town east of Rome on July 8, 2009. On the beginning day, parallel summits of the G-8 countries (chaired by Italy) and the G-5 (chaired by Mexico) were held. Then on July 9, there was a combined meeting of the G-8 and G-5 alongwith the international organiza-tions, Egypt and other major eco-nomies. Third day of the summit brought the African countries into the dialogue with the G-8 and the G-5, with the focus on food security.

The declaration expressed the joint commitment of the G-8 and G-5 to implementing rapidly the decisions taken at Washington and London in G-20 summits, including those on providing additional resources to the international financial institutions. The declaration committed the G-8 and the G-5 to facilitating the develop-ment, dissemination and mutually agreed transfer of clean, low carbon technologies, reducing carbon emis-sions and increasing energy effi-ciency. This is the first time in a G-8 and G-5 summit that a joint declara-tion has been issued.

Mini Pravasi Bhartiya Divas—

In a view to involving Indians living in Europe, the Government of India has decided to hold the next mini Pravasi

Bhartiya Divas in Hague on Septem-ber 19, 2009. The convention is expected to bring together the Indians to discuss their role in enhancing India-Europe cooperation, understand the opportunities and challenges faced by them in culture, heritage and tradition, as also trade and investment opportunities in India.

India Launched First Nuclear-powered Indigenous Submarine—

On July 26, 2009 India demonstrated its capability to indigenously build and operate a nuclear-powered submarine when Prime Minister Dr. Manmohan Singh launched INS Arihant (dest-royer of enemies) for sea trial in Visakhapatnam. DESTROYER OF ENEMIES ● Length : 110 metres ● Width : 11 metres ● Displacement : 6,000 tonnes ● Crew : Around 100 ● Induction : 2011 ● Speed : 30 knots

● It can remain under water for three months at a stretch, unlike India’s existing diesel-electric submarines that have to surface frequently to recharge their batteries and thus run serious risk of detection.

● Arihant still has to undergo rigorous testing.

● “We've got to get its heart ticking now,” said Advanced Technology Vehicle Director General Vice Admiral (retd) DSP Verma.

India has now joined a select group of five countries which possess the capability to build a nuclear-powered submarine. Submarine is

INS Arihant–India’s Nuclear-powered Submarine

equipped with anti-ship missiles, torpedoes and sensors to keep it

undersea for a prolonged period of time.

It took 11 years for the submarine to be built under the code name “AdvancedTechnologyVessel(ATV)”, with the strategic cooperation of the Russian Federation. The ATV pro-gramme has spawned a new era in cooperation among DRDO, Bhabha Atomic Research Centre (BARC), the Navy and public and private sectors, synergised their efforts to achieve a significants milestone. A nuclear-powered submarine is a much-more complex platform than any other vessel and India built one of its own is a great achievement. This is the unanimous assessment of experts of the world. The nuclear-powered submarine is a highly complex platform and safety regulations have to be adhered to. There are hundreds of systems and subsystems on the submarine. They have to work one after another. This is called setting-to-work.

Bhabha Atomic Research Centre built the mini-nuclear reactor that powers the submarine. DRDO developed the K-15 missiles. What enhances the scale of the achieve-ment is that INS Arihant will be fitted with India’s own K-15 ballistic missiles that can be launched from under water. The K-15 missiles, which are already under production, can carry both conventional and nuclear warheads. They have a range of 700 kms. They are 10·4 metres tall and weight 6·3 tonnes each.

On occasion of launching, the Prime Minister, Dr. Singh, said, “We do not have any aggressive desire nor do we seek to threaten anyone. We seek an external environment in our region and beyond that is con-ducive to our peaceful development and the protection of our value systems.Nevertheless,itis incumbent upon us to take all measures neces-sary to safeguard our country and keep pace with technological advancements worldwide.”

SPORTS

Cricket

Champions Trophy—Prize money hiked—The International

Cricket Council announced a new format for the Champions Trophy according to which only the top eight one-day teams will battle it out for an increased prize money of $ 4 million.

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Prize money for the title winner has been increased to a four-fold. The significant increase in prize money is just the first of a series of innovations which will mark out the ICC Cham-pions Trophy as a high-value tourna-ment.

Champions Trophy-2009—

Champions Trophy tournament will begin on September 22, 2009 with host South Africa locking horns with Sri Lanka at Centurian Park and will conclude at the Sams venue on October 5, 2009.

Unlike previous editions, only top eight ranked teams are eligible to play in the tournament, spread over 15 matches. The teams, Australia, England, India, New Zealand, Pakis-tan, host South Africa, Sri Lanka and the West Indies, have been divided into two groups of four, with the top two from each group advancing to the semi-final stage.

India-West Indies ODI Series—

India won the ODI series 2–1 against West Indies. Fourth and the final match of the series was washed away by rain, Mahendra Singh Dhoni was adjusted as the ‘Man of the Series’ for his consistent performance through-out the series. As a result of this victory, India achieved its second series win in West Indies. In 2002 also, India had won theseries in West Indies. In this series win, left-hander Yuvraj Singh Zoomed toa career best second place in the ICC ODI rankings which is currently topped by M. S. Dhoni.

Sri Lanka-Pakistan Test Series

—On July 24, 2009 in Colombo, Sri Lanka clinched the series 2–0, its first at home against Pakistan after five unsuccessful attempts and it provided Sangakkara with a winning start as a Captain. He hit an unbeaten century to steer Sri Lanka to a draw on the final day of final test.

SCORE BOARD Pakistan—1st Innings : 299. Sri Lanka—1st Innings : 233. Pakistan—2nd Innings : 425 for

nine decl.

Sri Lanka—2nd Innings : 391.

Tennis

Wimbledon 2009—On July 5,

2009 in London, Switzerland’s Roger Federer, came up as the most

successful Grand Slam Champion after beating Andy Roddick of the United States 5–7, 7–6, 7–6, 3–6, 16–14 in the men’s singles final. He won his record 15th Grand Slam title eclipsing USA’s Pete Sampras’ record of 14 major titles. With this title he again became the world’s No. 1, relegating Rafael Nadal of Spain to the second spot. Women’s Singles : In the women’s singles final played on July 4, 2009, Serena Williams of USA prevailed over her elder sister Venus Williams 7–6, 6–2 to claim her third Wimbledon women’s singles title. Men’s Doubles : In the men’s doubles final, Canada’s Daniel Nestor and Nenad Zimonjic of Serbia defeated Mike Bryan and Bob Bryan of USA 7–6, 6–7, 7–6, 6–3. Women’s

Doubles : In the women’s doubles

final, Serena Williams and Venus Williams of USA pipped Samantha Stotsur and Rennae Stubbs of Australia 7–4, 6–4. Mixed Dubles : Mark Knowles of Bahamas and Anna-Lena Groenefeld of Germany beat Leander Paes of India and his partner Cara Black of Zimbabwe 7–5, 6–3 to win the mixed doubles title.

Boxing

Indian Team for World Boxing Championship—The Indian Boxing

Federation on July 18, 2009 an-nounced a nine-member team for the World Boxing Championships to be held in Milan, Italy sinceSeptember 1 till 12.

The team : Nanao Singh (48 kg),

Suranjoy Singh (51 kg), Jitender Kumar (54 kg), Akhil Kumar (57 kg), Jai Bhagwan (60 kg), Manoj Kumar (64 kg), Vijender Singh (75 kg), Dinesh Kumar (81 kg), Manpreet Singh (91 kg).

Archery

Deepika is World Champion—

Deepika Kumari of India won the individual gold medal in the cadet recurve women section of the 11th Youth World Archery Championship in Ogden (Utah), United States on July 21, 2009. Deepika, a trainee at the Jamshedpur–based Tata Archery Academy, is the current senior National and sub-junior National Champion.

This is second time India has won a world title in archery. Palton Hansda became the first Indian to be the World Champion in 2006 in Mexico.

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It Includes

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‘‘Clear focus on target, regular study, study with concentration and

regular revision are the elements of my success.’’

—Ratish Kumar Mishra

Selected in U.P. CPMT-2009 (Rank-6)

[‘Competition Science Vision’ arranged an exclusive interview with Mr. Ratish Kumar Mishra who has

the credit of being successful with a high rank in U.P. CPMT and also in PMT of AMU. For his brilliant

success he deserves all praise and our hearty congratulations. This important interview is published here in

its original form.]

CSV—Congratulations on your

brilliant success.

Ratish—Thank you.

CSV—Before knowingyour result what did you think about those who achieve top positions ?

Ratish—I used to think that they

were born intelligent persons.

CSV—Achieving top position has

come as surprise to you or were you confident of achieving it ?

Ratish—I was confident of

success but it was surprising when I heard that I have got 6th rank in U.P. CPMT.

CSV—What do you think is the

secret of your success ?

Ratish—Clear focus on target,

regularstudy,studywithconcentration and regular revision are elements of my success.

CSV—In how many attempts did

you get this success ?

Ratish—I took three attempts. CSV—What were the

short-comings in your preparationfor earlier attempts ? How did you make up for them this time ?

Ratish—I did not revise the

whole course and also I left some topics which I thought were less important.

Failure in earlier attempts made me realise that all the topics are important and we should revise them all before examination. So I revised the whole course twice.

CSV—From where did you get

the inspiration of choosing a medical career ?

Ratish—My brother is also a

Doctor and also it was my childhood dream.

CSV—From when did you start

the preparation for it ?

Ratish—After 12th class.

CSV—What planning did you

make for preparation ? Please tell something in detail.

CSV gives latest and

important points regarding pre-medical tests of various pre-medical institutes. I have found it extre-mely useful in my examination.

—Ratish Kumar Mishra Ratish—My studies were mainly

based on text-books. I went through all the books. Questions in PMT examinations are mainly based on concepts. So I mainly cleared my concepts in every topic.

CSV—How much time did you

devote daily andregularly for Physics, Chemistry, Zoology and Botany ?

Ratish—I used to study 8-10

hours daily. I devoted only two or three subjects daily. For each subject I gave 3-4 hours daily.

CSV—Out of the above four

subjects,towhich subject did you give more weightage and why ?

Ratish—I mainly gave weightage

to Biology because I find it hard to learn so many of facts. I also gave importance to Physics.

CSV—Did you make complete

study of alltopics or of some selective topics ?

Ratish—Yes, I made complete

study of all the topics.

CSV—How did you give final

touches to your preparation ?

Ratish—In Biology, I revised

those topics in which a lot of facts have to be clearly understood and remembered. In Physics, I went through all the formulae and basic concepts. In Chemistry, I revised inorganic and organic portions.

CSV—Did you prepare notes ? Ratish—Yes, I prepared notes.

Bio-Data

Name—Ratish Kumar Mishra Father’s Name—Mr. Ram Anuj

Mishra

Mother’s Name—Mrs. Gayatri

Mishra

Educational Qualifications— H.S./Std. X—86% (City Montessori

School Gomti Nagar, Lucknow), 2004.

Inter/Std XII—86% (City Montessori

School Gomti Nagar, Lucknow), 2006.

Special Achievements—

● CPMT—6th rank ● Selected in AMU PMT.

CSV—What was your attitude for

solving numerical questions ? What weightage did you give them ?

Ratish—I did give them proper

weightage during my preparation, while solving numericals I keenly observed that what are the values given and what is asked ? Then I applied the formula or concept related to it.

For that I had gone through the derivation and concept used in formula applied.

CSV—How much time is

suffi-cient for preparing for this examina-tion ?

Ratish—For an average student

2 years.

CSV—From what level of

edu-cation should an aspirant begin pre-paring for it ?

(13)

Ratish—Oneshouldbegin it from class 11th.

CSV—What was your order of

preference for various branches for which this test is held ?

Ratish—Only MBBS.

Personal Qualities

Hobbies—W a t c h i n g c r i c k e t ,

playing football

Ideal Person—My brother, Dr.

Manoj Kumar Mishra

Strong Point—My determination Weak Point—I early loose my

concentration

CSV—Please mention various

books in each subject and magazines on which you based your preparation.

Ratish—Physics : N o o t a n

Physics by Kumar and Mittal

Chemistry : O. P. Tondon Zoology : Ramesh Gupta and

NCERT books.

Botany : M. P. Kaushik and

NCERT books.

Bio : Modern ABC of biology.

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UPKAR PRAKASHAN, AGRA–2

DELHI

Code No. 971

Price : Rs.

299/-(Technical Cadre)

Station Controller Train Operator Section Engineer Junior Engineer Junior Station Controller

Including

Previous Years’

Solved Papers

For–

By : Dr. Lal & Jain

Magazine : CSV magazine which

contains all the above subjects and is highly useful.

CSV—Did you take coaching in

your preparation ?

Ratish—Yes, I have joined New

Light Coaching Institute, Lucknow Centre. I was very much impressed with the Director of New Light Dr. S. P. Singh because his style of teach-ing of Bio is very good.

CSV—What help do the science

magazines render in the preparations for this examination ?

Ratish—They give better

know-ledge in G.K. and important points regarding various topics.

CSV—What will be your criterion

for selecting a magazine for these examination ?

Ratish—Which provides latest

information and model papers.

CSV—Whatis your opinion about ourCompetitionScienceVision ? How much helpful and useful do you find it ?

Ratish—Itgiveslatest and impor-tant points regarding PMT. I find it

really helpful in preparation of CPMT.

CSV—Please suggest in what

way CSV can be made more useful for medical aspirants.

Ratish—They should give more

model paper based on All India pattern.

CSV—Please mention your

position in the merit list as well as the marks obtained in different subjects. Whatwasyouraggregatepercentage of marks ?

Ratish—I got 6th rank in U.P.

CPMT. Physics—49 marks Chemistry—47 marks Zoology—45 marks Botany—47 marks Total—188 marks CSV—What books/magazines/

newspapers did you read for G.K. preparations ?

Ratish—CSV, Dainik Jagaran.

(Continued on Page 821

)

(14)

Physics

1. What is dimensions of ‘conductance’ ?

➠ [C] =

1

[R] = [M– 1 L– 2 T3 A2]

2. When horizontal range of a projectile is n times the

maximum height, then

➠ tan

θθθθ = 4 n 3. What are ‘field forces’ ?

These are the forces in which contact bet-ween two objects is not necessary. Example : Gravitational force between two bodies and electrostatic force between two charges.

4. When a particle moves with constant speed in a circle its velocity and acceleration both have

➠ Constant magnitude but continuously

changing directions

5. What is the principle of conservation of momentum ?

If no external force acts on a system of two or more bodies, then the total momentum of the system remains constant

6. Changeinmomentum of projectile at the highest point of its trajectory is

mv sin θθθθ

7. What is Dalton’s law of partial pressure ?

The pressure exerted by a mixture of several gases equals the sum of the pressures exerted by each gas occupying the same volume as that of the mixture.

8. The maximum speed with which a car can turn round a curve of radius r is given by

vmax = μμμμ rg

where μ is the coefficient of friction

9. What is equation of stationary wave : when the wave is reflected from a free boundary ?

y = – 2a cos 2ππππx

λλλλ . sin

2ππππt T

10. The angle θ which a cyclist should make with the vertical while taking a circular turn of radius r with

velocity v is given by

➠ tan

θθθθ = v2 rg 11. The relations between P, V and T in an adiabatic

process are

➠ (a) PV

γγγγ = constant (b) TVγγγγ – 1 = constant (c) P1 – γγγγ Tγγγγ = constant

12. The relation between pressure (P) and the kinetic energy (E) of its molecules per unit volume is

➠ P =

2 3 E

13. When object is placed at infinity longitudinal chromatic aberration is given by

fR – fV = wfY 14. Work done in an adiabatic process is given by

➠ W =

R

γγγγ – 1 (T1 – T2) 15. Capacitanceof a parallel plate capacitor filled partially

with some dielectric medium, is

➠ C

pd = εεεε0A

d – t

[

1 –

( )

1

]

K

16. For what purpose are heavy water and cadmium rods used in a nuclear reactor ?

➠ Heavy water as moderator to slow down

neutrons. Cadmium rods as controller to control the rate of fission

17. Impedance of L-C-R circuit is given by

Z = R2 + (XL – XC)2 (where XL = ωωωωL = inductive reactance;

XC = 1

ω ω ω

ωC = capacitive reactance) 18. For pair-production it is essential that the energy of

γ-photon must be at least

➠ 1·02 MeV (= 2

×××× 0·51 MeV)

19. What are the drawbacks of ‘liquid drop model’ ?

(a) It cannot explain the existence of magic numbers

(b) It cannot explain why only certain ener-gies of radiations are emitted by a nucleus

(c) It does not explain magnetic moment of nucleus

20. The relation between half life T1/2 and mean life τ of a radioactive substance is

➠ T

1/2 = 0·6931 ττττ

(

T1/2 = 0·6931

)

λλλλ and ττττ = 1 λλλλ

Chemistry

21. A substance which has some of the structure of solids and some of the freedom of motion associated with liquids, is called

➠ Liquid Crystal

22. What is the IUPAC name and symbol of an element having atomic number 111 ?

➠ Un-un-unium (Uuu)

23. When mercury (Hg) was cooled below 4·1 K its resistance to an electric current becomes zero. It was first observed by

(15)

24. What is the unit of measurement of nuclear dis-tances ?

➠ Femtometre (1 fm = 10

– 15 m) 25. The most direct and accurate means for determining

atomic and molecular weights is provided by

➠ Mass-spectrometer

26. Why are mercury (I) compounds diamagnetic, despite the presence of an unpaired electron in Hg+ ?

➠ Due to formation of [Hg—Hg]

2+ 27. The process of reheating a quenched steel to relieve

internal stresses, is called

➠ Tempering

28. What is the rubeanic acid ?

➠ Dithio oxamide, NH

2—C || S —C || S —NH2

29. Hydrolysis of an ester in the presence of a base is termed as

➠ Saponification

30. Whatisthetemperature known as, above which a gas cannot be liquefied ?

➠ Critical temperature

31. The energy required to decompose an atomic nucleus into its component protons and neutrons is called

➠ Nuclear binding energy

32. Which fatty acid is the major constituent of glyceryl esters present in castor oil ?

➠ Ricinoleic acid, C

17H32 (OH) COOH

33. A reaction in which two substances react through an exchange of their component ions, are called

➠ Metathesis reaction

34. What is the trade name of heavy medicinal liquid paraffin, extensively used as a mulling agent in spec-troscopy ?

➠ Nujol

35. The intermolecular forces resulting from attractions between induced dipoles are known as

➠ London dispersion forces

36. What is the use of bromochlorodifluoromethane (B.C.F.) ?

➠ Used in fire extinguishers

37. A solid whose molecular arrangement lack, a regular, long-range pattern is called

➠ Amorphous solid

38. What is the name of sodium aluminium silicate con-taining sulphur having a beautiful blue colour ?

➠ Lapis lazuli

39. The net positive charge experienced by an electron in a many-electron atom, is called

➠ Effective nuclear charge

40. What is the IUPAC name of chloral hydrate ?

➠ 2, 2, 2-trichloro ethanediol

Zoology

41. What is called small calcareous granules found in the inner ear of certain mammals ?

➠ Otolith

42. What is called the creation of mutation ?

➠ Mutagenesis

43. What is called the opening of the occipital bone of skull through which the spinal cord passes ?

➠ Foramen magnum

44. How many membranes comprise the nuclear mem-brane ?

➠ Two

45. Which anticoagulant is present in the saliva of leech ?

➠ Hirudin

46. What accepts the final electrons in electron transport system ?

➠ Oxygen

47. Which type of mutation involves a change in nucleo-tide and ultimately a change in a specific codon ?

➠ Point mutation

48. What was virtually absent in primitive atmosphere ?

➠ Oxygen

49. What is called the peculiar stage in Plasmodium

merozoites which appear like sepals and petals of a flower ?

➠ Rosette stage

50. Which vector should be eradicated for the prevention of African sleeping sickness ?

➠ Tse-tse fly

51. To which kind of disorder, the systemic lupus erythematosus is associated ?

➠ Autoimmune disease

52. What is the unit of natural selection ?

➠ Individual

53. What is called a catalytically active complex formed by an apoenzyme and a coenzyme ?

➠ Holoenzyme

54. What is called a movement response to air or water ?

➠ Rheotaxis

55. What is called an artery in mammals that arises from an arch of the aorta and divides to form the right carotid and right subclavian arteries ?

➠ Innominate artery

56. What is usually lost from bones during aging ?

➠ Calcium and phosphate

57. What is called a movement response to air or water current in Amoeba ?

➠ Rheotaxis

58. What type of nutrition is found in Monocystis ?

➠ Saprozoic

59. Which enzyme is involved in light production in certain insects ?

➠ Luciferase

60. In nearsightedness effect the image does not focus on which part of eye ?

(16)

Botany

61. How many ATP molecules are formed per glucose molecule by substrate level phosphorylation ?

➠ 4 ATP molecules

62. Which family is commonly called gourd family ?

➠ Cucurbitaceae

63. What term is used for a change in the permeability of a cell’s plasma membrane that allows sodium ions to diffuse rapidly into the cell’s interior ?

➠ Depolarization

64. What is called the process by which a cell secretes macromolecules by fusing a transport vesicle to the plasma membrane ?

➠ Exocytosis

65. What does taxonomy deal with ?

➠ Naming of organisms

66. The resolving power of an electron microscope is how much greater than the resolving power of a light microscope ?

➠ One thousand times

67. What does phloem transport usually from the leaves to roots ?

➠ Organic nutrients

68. What type of energy was used by Miller-Urey experi-ment ?

➠ Electric spark

69. What is the correct name of slow viruses ?

➠ Prion

70. In which group all unicellular plants and animals with true nuclei are included ?

➠ Protista

71. To which family Atropa belladona belongs ?

➠ Solanaceae

72. What type of Saccharomyces, a fungus is ?

➠ Nonmycelial unicellular

73. What is the shape of microspore of Cycas ?

➠ Tetrahedral

74. What type of fruit dispersal is generally found in Papaveraceae ?

➠ Censar mechanism of fruit dispersal

75. What is called a group of conjugated proteins in which one of the FAD or FMN is bound as prosthetic group ?

➠ Flavin

76. What causes ‘early blight’ of potato ?

➠ A fungus,

Alternaria solani 77. Which process is inhibited by the drug streptomycin ?

➠ Prokaryotic translation

78. What type of ovule is reported to have been found in Pea ?

➠ Campylotropous

79. Which is the earliest era in the geologic record ?

➠ Precambrian

80. How many codons are present in valine, an amino acid ?

➠ Single codon

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(17)

1. Wave Motion

It is defined as a disturbance that travels through the medium due to repeated periodic motion of its particles about their mean position, each preceding particle handing over the disturbance to next.

Points to Remember

(i) Wave represents transfer of energy and not transfer of mass.

(ii) A wave which moves forward and thus, transfers energy along its direction of motion is called progressive wave while a wave in which there is no transfer of energy and which remains confined to a fixed space is called stationary wave.

(iii) Mechanical waves require some material media for their propagation as they require properties of inertia and elasticity.

(iv) Electromagnetic waves like light waves can travel with-out medium. Thus, they can travel through vacuum. (v) Sound waves are longitudinal mechanical waves and

they can propagate in solids, liquids and gases. (vi) The audible frequency is from about 20Hz to about

20,000 Hz. A longitudinal mechanical wave whose frequency is above the audible range is called an ultra-sonic wave and such wave whose frequency is below the audible range is called infrasonic wave.

(vii) Some waves like ripples on water surface are neither purely transverse nor purely longitudinal.

2. Two Types of Wave Motion

(a) Transverse wave—(i) The particles of the

medium vibrate at right angles to the direction of propa-gation of the wave.

(ii) Crests and troughs are produced.

(iii) It is possible in media which possess elasticity of shape or rigidity e.g., solids or at best over the surface of

liquids.

(iv) It is because a liquid surface has property of surface tension which resists any deformation of shape.

(v) Transverse wave is not produced or possible in gases.

( b ) Longitudinal wave—(i) The particles of the

medium vibrate along the direction of propagation of the wave.

(ii) Compressions and rarefactions are produced. (iii) The media must have elasticity of volume. (iv) Longitudinal waves are possible in all media i.e.,

solid, liquid and gas.

(v) It is because all these resist any change in volume.

3. Characteristics of Wave Motion

(a) Frequency (n)—The number of waves which pass a point per unit time is called the frequency of the wave motion.

(b) Wavelength (λλλλ)—It is shortest distance between

two points in the same phase.

(c) Time period (T)—Time taken to complete one

vibration is called time period.

(d) Amplitude (A)—The maximum displacement of a

vibrating particle from mean position is called its amplitude.

(e) Wave velocity (v)—The distance travelled by the

wave in one second is defined as its velocity.

Note—

(i) The velocity of the particles of the medium is different from the velocity of the wave.

(ii) Wave velocity = frequency × wavelength

v = n λ

(iii) The relation v = n λ holds good for any type of

wave motion-transverse or longitudinal

(iv) When a given wave passes from one medium to the other, its frequency does not change.

v1 v2

= λ1 λ2

(f) Phase—The phase represents the state or

condi-tion of a vibrating particle. After a distance λ, the particles are in same phase. Also a particle comes to the same phase after completing one rotation or an angle of 2π radians. So λ path corresponds to 2π phase change.

Phase difference = 2π

λ × path difference

(g) Wave front—When a wave passes through a

medium the surface that gives the continuous locus of all points in the same phase of vibration at a particular instant, is called the wavefront. The wavefront advances through the medium with the wave velocity. If the medium is homogeneous and source is a point, the wavefront is spherical. For a linear source in a homogeneous medium, the wavefront is cylindrical. For the case of source being at infinity, the wavefront is plane.

4. Equations of a Plane Progressive Wave

In +x direction In – x direction (a) y = a sin 2π

( )

t T – x λ y = a sin 2π

( )

t T + x λ (b) y = a sin (ωt – kx) y = a sin (ωt + kx) (c) y = a sin ω

( )

t – x v y = a sin

(

ωt +

)

x v (d) y = a sin 2πn

( )

t – xv y = a sin 2πn

( )

t + xv

(e) y = a sin k (vt – x) y = a sin k (vt + x) (f) y = a sin

λ (vt – x) y = a sin

(18)

where, ω = 2π T = 2πn k = 2π/λ v = n λ = λ T = ω k

Note—The above equations represent only a simple

plane progressive wave without attenuation (amplitude gradually decreasing with distance). But in the case of propagation of actual wave through a medium, its amplitude gradually diminishes due to resisting effect of viscous medium. Due to loss of energy, the amplitude decreases exponentially with distance and the equation of the attenuated plane progressive wave is given by

y = ae αx sin

(

ωt –

)

λx where, α is the attenuation constant.

5. Velocity of Longitudinal Waves in Elastic

Medium

(a) Newton’s formula—Newton proved that when

longitudinal waves (sound) move in elastic medium, the velocity is given by

v = Ed

where E is the modulus of elasticity of the medium and d

is its density.

Note—Wave velocity in a medium is fixed. Wave

velocity is a material constant. It does not depend on wavelength, frequency and intensity.

(b) For solids—Modulus of elasticity

E = Young’s modulus of elasticity = Y

v = Y

d

(c) For liquids—Modulus of elasticity

E = Bulk modulus of elasticity = B

v = Bd

( d ) For gases—For a gaseous medium, Newton

assumed that the propagation of longitudinal wave is an isothermal process (temperature remains constant). In this case, modulus of elasticity

E = Pressure of the gas = P

v = Pd

Note :

(i) The experimental results did not confirm to Newton’s assumption. Laplace corrected the formula by arguing that sound waves travel adiabatically. Hence,

v = γPd = γRT M =

γ k T

m

where,T is absolute temperature of the gas,M is its molecular weight and R is universal gas constant.

k = RN = Boltzmann constant N = Avogadro number

m = MN = Mass of one molecule (ii) γ = Cp/Cv (ratio of specific heats)

= 1·67 for monoatomic gas = 1·40 for diatomic gas = 1·33 for polyatomic gas (iii) γ = 1 + 2

n

where, n is degree of freedom of gas molecules n = 3 for monoatomic gas

n = 5 for diatomic gas

n = 6 for triatomic or polyatomic gas

(iv) Velocity of longitudinal wave in

solid medium > liquid medium > gaseous medium

6. Effect of Physical Conditions on Velocity of

Sound

(a) Effect of pressure—With the change of

pres-sure, the velocity of sound in a gas remains unchanged, that is, there is no effect of pressure on the velocity of sound in a gas.

(b) Effect of temperature—Velocity of sound ∝ √⎯T. Thus, the velocity of sound is directly proportional to the square root of the absolute temperature. i.e.,

v t v0 = Tt T0 = 273 + t 273 or vt = v0

(

1 +

)

t 273 1/2

Note —For small value of t (t < < 273)

vt ≈ v0

(

1 +

)

t 2 × 273 vt ≈ v0

(

1 + 0·00183t

)

In air, v0 = 332 m/s ≈ 1100 ft/sec ∴ vt ≈ (332 + 0·61 t) m/s ≈ (1100 + 2t) ft/s

That is, velocity of sound increases by 0·61 m/s or 61 cm/s or 2 ft/sec per degree celsius rise in temperature.

(c) Effect of humidity—With the decrease in density

of the medium the velocity of sound increases. The moist air is lighter than the dry air. Therefore, the velocity of sound in moist air is more than the velocity of sound in dry air.

(19)

Some Interesting Facts About Sound

1. There is pressure variation in longitudinal waves. But there

is no such pressure variation in the case of transverse waves.

2. Sound waves reflect and refract obeying the same laws as followed by light but they do not suffer dispersion like light waves, when passed through a prism of suitable medium. This is due to fact that the velocity of sound in a medium is same for all wavelengths.

3. Sound waves are reflected like light waves when they strike an obstacle like the wall of a building, rows of trees, hillside etc. They also follow exactly the same laws of reflection as followed by light waves. The audible wave-length range varies from 0·0166 m to 16·6m, so for ref-lection of sound waves, a comparatively large surface is required, whereas light waves can be reflected from a very small surface area as their wavelength is very small. 4. Echo is produced by reflection of sound waves from an

extended reflector like a long wall or cliff and can be differentiated from the original sound. The distance of the reflecting surface should be at least 33·2 metre away from the source.

5. Sound also exhibits the phenomenon of total internal reflection as exhibited by light. This happens when sound waves travelling in a medium in which they have less velocity, meet the surface of another medium in which sound waves have larger velocity, at an angle more than critical angle.

6. Sound travels longer distance at night than during day. 7. The sound waves in the frequency range 20Hz—20,000 Hz

are audible to human ear. Sound waves below 20 Hz are called infrasonic waves while those above 20,000 Hz are called ultrasonic waves. Ultrasonic waves are not audible to human ear. These are produced naturally by bats and help it in avoiding collisions with obstacles while flying. 8. Ultrasonic waves can be produced by Piezo electric

oscillator, magnetostriction oscillator and detected by Kundt’s tube, sensitive flames, thermal detectors and quartz crystal detectors.

9. The sound in a building or auditorium does not die immediately after the source has ceased to produce it. It continues for sometime because of multiple reflections. This persistence of audible sound after the source has ceased to emit waves is called reverberation.

(d) Effect of wind velocity—The velocity of wind

effects the velocity of sound. If the wind blows in the direction of propagation of sound, the velocity of sound v

will be replaced by (v + ω) and if it blows in the opposite

direction,the velocity of soundv will be changed to(v – ω).

If the wind blows in any inclined direction, ω is to be replaced by its appropriate component.

7. Intensity of Sound Waves

Intensity of wave propagating in a medium is defined as the amount of energy transferred per unit area per unit time in normal direction. It is given by

I = 1 A ΔW Δt watt/m2 I = 2π2ρa2n2.v Note :

(i) When wave travels uniformly in all directions from a small source (point source), the intensity varies inversely as the square of the distance,

I ∝ 1

r 2

or I1r12 = I2r22

(ii) Threshold of audibility for intensity is 10–12 W/m2

8. Unit of Sound Intensity

The absolute unit of intensity of sound is W/m2. But

for practical considerations, the relative intensity or intensity level is of much importance.

Intensity level is the ratio of given value (I) to the basic standard intensity (I0 = 10–12 W/m2). Thus, practical

unit for intensity level measurement is decibel. Intensity in decibel = 10 log10 I

I0 where, I0 = 10–12 W/m2

Intensity in Bel = log10I I0

Intensity Level of Various Sounds

1. General level of noise 10 db

2. Soft music 40 db

3. Ordinary conversation 60–70 db

4. Busy traffic 7–85 db

5. Alarm clock 80 db

6. Jet air port 115–120 db

7. Landing area of air craft carrier 150–155 db

9. Loudness

The intensity of sound refers to external or objective measurement, whereas loudness refers to internal or sub-jective aspect. The loudness of a sound is the magnitude of the auditory sensation produced by sound.

The loudness of sound increases with intensity of sound given by the psychological law known as Weber-Fechner law which is as

L = K log10I

I0 where K is a constant.

Sensitivity of ear

L = K log I (as I0 is constant)

d L d I =

K I

d L

d I is known as sensitivity of ear which decreases

with increase in the intensity of sound.

Unit—The unit of loudness is ‘Phon’.

10. Pitch

It is the characteristic, which differentiates the notes of same loudness and quality. It is an audio sensation which depends on frequency. Higher the frequency, higher is the pitch and more shrill is the sound. Sound of lower frequency, hence, of lower pitch corresponds to dull or grave sound. The voice of children and women are shrill due to high pitch, whereas voice of adult persons is grave due to lower pitch.

References

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