capephysics labs2 v4

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BISHOP ANSTEY HIGH SCHOOL EAST AND

TRINITY COLLEGE EAST (BATCE)

Sixth Form

TRINCITY, TRINIDAD AND TOBAGO, WEST INDIES TRINCITY, TRINIDAD AND TOBAGO, WEST INDIES

CENTRE NO. 160570

CXC CAPE Physics

Unit 2 Lab Manual

2015-2016

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cc



Copyright by Bishop Anstey High School East and Trinity College East

(BATCE) 2015

All Rights Reserved

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Rules and Regulations of the Laboratory

1.

1. All experAll experimeiments in nts in thithis s lablaboraoratortory y manmanual must ual must be be perfperformormed ed and and wriwrittetten n scriscriptspts for each experiment must be submitted to your class teacher to obtain a practical for each experiment must be submitted to your class teacher to obtain a practical coursework mark.

coursework mark. 2.

2. Commencement of sessions: YCommencement of sessions: You are expected to be ou are expected to be at your experiment statiat your experiment station punc-on punc-tually.

tually. 3.

3. PreparaPreparation: tion: LaboraLaboratory manualtory manuals are availas are available at the class websitble at the class website. e. These manuaThese manualsls contain a description of all the laboratory experiments that must be performed as contain a description of all the laboratory experiments that must be performed as part of the

part of the requirerequirements for CAPE Physics SBAsments for CAPE Physics SBAs. . StudenStudents are ts are requirrequired to ed to prepareprepare adequately for their assigned laboratory experiment prior the start of the session. adequately for their assigned laboratory experiment prior the start of the session. Preparation includes reading the experimental description adequately and Preparation includes reading the experimental description adequately and perform-ing the necessary research to enable one to perform the experiment with ease in the ing the necessary research to enable one to perform the experiment with ease in the laboratory.

laboratory. 4.

4. StartiStarting experimeng experiments: nts: All laboratAll laboratory equipmenory equipment must be t must be checkechecked prior to d prior to studenstudentsts comme

commencing their experincing their experimentsments. . DO NOT switch ON equipmenDO NOT switch ON equipment until it t until it is checkedis checked by your

by your teacheteacher!!r!! 5.

5. LaboratLaboratory report submisory report submission: sion: All laboraAll laboratory reports must be submittory reports must be submitted to the classted to the class teache

teacher ONLr ONLY on Y on the date it is the date it is due. due. If your laboratory report submiIf your laboratory report submission date fallsssion date falls on a public holiday, then the report must be submitted on the next available school on a public holiday, then the report must be submitted on the next available school day. Laboratory reports must be submitted with the appropriate cover sheet (with all day. Laboratory reports must be submitted with the appropriate cover sheet (with all the details complet

the details completed) and ed) and a signed a signed anti-anti-plagiaplagiarism sheet. rism sheet. StudenStudents will given untilts will given until the followi

the following day, of ng day, of performperforming the ing the experiexperiment, at ment, at 10:3010:30am (break am (break time) to time) to submisubmitt their lab reports. At this time the student would sign the teachers’ lab record book as their lab reports. At this time the student would sign the teachers’ lab record book as evidence the lab was submitted.

evidence the lab was submitted. 6.

6. AbsentAbsenteeismeeism: : StudeStudents absent from any experiment must provnts absent from any experiment must provide a ide a medicmedical/eal/excusexcuse to administration.

to administration. 7.

7. StudenStudents who are absent on the day of ts who are absent on the day of the lab practicthe lab practical actial activity woulvity would be scheduledd be scheduled with the lab technician to perform the lab within a one week period from the date of with the lab technician to perform the lab within a one week period from the date of

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the missed lab

the missed lab. . They are to sign They are to sign the lab technicithe lab technician’an’s rcord s rcord book with the date the book with the date the lablab was performed

was performed. . This report would be This report would be due the due the follofollowing day at wing day at 10:30a10:30am.m. 8.

8. StudeStudents who fail to submit their lab reportnts who fail to submit their lab reports at the s at the deadlideadline would be marked as none would be marked as no work submitt

work submitted. ed. SpeciaSpecial l alloallowancewances s woulwould d be be givgiven to en to studetstudetns with ns with a a valvalid excuse,id excuse, for example a death in the family or physical injury. This excuse must be conﬁrmed for example a death in the family or physical injury. This excuse must be conﬁrmed via a note and phone call from the parents or medical where applicable, on the day via a note and phone call from the parents or medical where applicable, on the day the report is due.

the report is due. 9.

9. LaboraLaboratory requiremtory requirements: ents: For each laboratorFor each laboratory session students are required to bringy session students are required to bring their laboratory manual, writing paper, graph pages, a scientiﬁc calculator and other their laboratory manual, writing paper, graph pages, a scientiﬁc calculator and other stationery items inclusive of pen/pencils, erasers, rulers and geometrical instruments stationery items inclusive of pen/pencils, erasers, rulers and geometrical instruments (if needed for the laboratory experiment).

(if needed for the laboratory experiment). 10.

10. LaboraLaboratory attirtory attire: e: StudenStudents are required to wear a laboratorts are required to wear a laboratory coat and closed shoesy coat and closed shoes while present in the laboratory.

while present in the laboratory. 11.

11. WWork stationork stations: s: StudenStudents must remain at their assignets must remain at their assigned work station for the durationd work station for the duration of the laborato

of the laboratory session. ry session. If a If a studenstudent needs to leave the work statt needs to leave the work station, permissiion, permissionon must be sought and granted from the class teacher.

must be sought and granted from the class teacher. 12.

12. Difficulties witDifficulties with an experiment: Students experiencing difficulties with experimenth an experiment: Students experiencing difficulties with experimentss should seek assistance from their class teacher.

should seek assistance from their class teacher. 13.

13. At the end of each laboratorAt the end of each laboratory session: y session: At the end of each experimeAt the end of each experiment, studentnt, students ares are req

requiruired ed to to taktake e all theiall their r resuresults to lts to thetheir ir teateachecher r for revifor review and ew and corcorrectrectionion. . TheThesese results pages must be signed by the teacher and must be included in the laboratory results pages must be signed by the teacher and must be included in the laboratory report. The signed results pages must not be altered after the teacher has ﬁxed his/her report. The signed results pages must not be altered after the teacher has ﬁxed his/her signature. Students must seek the permission of the teacher prior to the exiting of the signature. Students must seek the permission of the teacher prior to the exiting of the labora

laboratory at tory at the end the end of each of each sessionsession. . AdditAdditionallionallyy, , before studentbefore students s leavleave e their work their work station they must ensure that they have removed all their personal belongings and station they must ensure that they have removed all their personal belongings and rep

replaclaced ed all equiall equipmepment to nt to the desigthe designatnated ed arearea. a. A A checheck ck of of equequipmipment assigent assigned toned to each student will be made by the technicians at the end of each laboratory exercise. each student will be made by the technicians at the end of each laboratory exercise. Students should not leave the laboratory until this check is made. Students will have Students should not leave the laboratory until this check is made. Students will have to pay

to pay a compensatia compensation fee on fee for missing or for missing or broken equipmbroken equipment.ent. 14.

14. CopyiCopying and plagiaring and plagiarism in the lab scripts are strictsm in the lab scripts are strictly forbiddly forbidden. en. PlagiPlagiarized woarized work rk will not be marked.

will not be marked. 15.

15. GeneraGeneral rules: l rules: StudeStudents are not permitted to eat, drink or smoke in the laboratorynts are not permitted to eat, drink or smoke in the laboratory.. The use of the internet is strictly permitted for laboratory research only.

The use of the internet is strictly permitted for laboratory research only. 16.

16. MobMobile phonile phones: es: The use of The use of mobmobile phonile phones is es is not permnot permittitted for ed for the duratthe duration of ion of thethe laboratory session unless approval is given.

laboratory session unless approval is given.

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Policy Principles

Practical work and lab reports are an important part of the student’s understanding of the Practical work and lab reports are an important part of the student’s understanding of the subject area. They provide an avenue where theory taught in the classroom can be tested, subject area. They provide an avenue where theory taught in the classroom can be tested, applie

applied d and/or proveand/or proved. d. PractiPractical work cal work engageengages s studenstudents, helps ts, helps them to them to devdevelop importanelop importantt skills, to understand the process of scientiﬁc investigation and develop their understanding skills, to understand the process of scientiﬁc investigation and develop their understanding of concepts.

of concepts.

Lab Reports form 20% of the student’s Caribbean Advanced Proﬁciency Examinations Lab Reports form 20% of the student’s Caribbean Advanced Proﬁciency Examinations (CAPE) Physics grade.

(CAPE) Physics grade.

Timely submission of work ensures students can receive timely feedback from their Timely submission of work ensures students can receive timely feedback from their tea

teachechers. rs. AlsAlso o scriscripts writtpts written en up up duriduring ng the practithe practical actical activitvity y ensensures that ures that the studenthe studentsts recall inform

recall information clearlation clearly about y about the experimethe experimental procedurntal procedure e (e.g. (e.g. the method, sources of the method, sources of error, teacher’s guidelines).

error, teacher’s guidelines).

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Format for Written Reports

0. Cover Sheet

Title of Experiment, your name, date that experiment was performed, partners’ names. Title of Experiment, your name, date that experiment was performed, partners’ names. (First and last names.

(First and last names. Get the spelling right!)Get the spelling right!)

1. Title

Ti

Titles should be straightfotles should be straightforwardrward, , informinformatiative, and less ve, and less than ten words (i.e. than ten words (i.e. Not "Lab #4"Not "Lab #4" but "Lab #4: Sample Analysis using the Debye-Sherrer Method").

but "Lab #4: Sample Analysis using the Debye-Sherrer Method").

2. Aim/Objective(s)

3. Theory/ Introduction

1-2 paragraph

1-2 paragraphs. s. SummaSummarize the basic physics of your experimerize the basic physics of your experiment. nt. IncludInclude equations ande equations and other principle things the reader would need to know in order to understand the experiment. other principle things the reader would need to know in order to understand the experiment. Keep it short!

Keep it short! If there are

If there are standastandard or rd or acceptaccepted values known these should be included in this section.ed values known these should be included in this section.

4. Apparatus

This can usually be a simple list, but make sure it is accurate and complete. This can usually be a simple list, but make sure it is accurate and complete.

5. Diagram

These should be clearly labelled with a title. These should be clearly labelled with a title.

6. Method/ Procedure/ Experimental Details

This section describe

This section describes s the process in the process in chronolchronologicaogical order. l order. Using clear paragraph structuUsing clear paragraph structurere (or step by step format), explain all steps in the order they actually happened, not as they (or step by step format), explain all steps in the order they actually happened, not as they

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wer

were e suppsupposeosed d to happento happen. . If you’If you’ve done it ve done it rigright, anotheht, another r reseresearcarcher shoulher should d be able tobe able to duplicate your experiment. It is always written in past tense.

duplicate your experiment. It is always written in past tense.

7. Precautions & Sources of Error

Indicate what steps were taken to reduce/eliminate random and systematic errors. Indicate what steps were taken to reduce/eliminate random and systematic errors.

Note: Mistakes are

Note: Mistakes are not classiﬁenot classiﬁed as d as errors.errors.

8. Results

The original raw data that you take in the lab. This should be easy to follow, in tabular form. The original raw data that you take in the lab. This should be easy to follow, in tabular form. Poor data recording skills lead to poor writeups. If your raw data is illegible, the grade will Poor data recording skills lead to poor writeups. If your raw data is illegible, the grade will suffer. The table should have a title and include the uncertainty of the measurement as well suffer. The table should have a title and include the uncertainty of the measurement as well as the unit in the heading (e.g. Variable

as the unit in the heading (e.g. Variable ± ± uncertainty in the measurement/ unit). uncertainty in the measurement/ unit).

9. 9. Sample Calcul

Sample Calculations

ations

Include a few of your calculations in this section, e.g. one of each type. Do not show each Include a few of your calculations in this section, e.g. one of each type. Do not show each and every calculation.

and every calculation.

10. General Analysis

The computed results are shown in a clear and concise manner utilizing properly labelled The computed results are shown in a clear and concise manner utilizing properly labelled tables and graphs.

tables and graphs. “T“Table/able/Graph showiGraph showing results” is ng results” is not an not an approprappropriate title. iate title. Each columnEach column of the

of the tabtable must have a le must have a headheading and unitsing and units, , if appliif applicabcable. le. TTablables must be es must be borborderedered d byby 4

4 linlines es and neatand neatly constrly constructucted. ed. If a If a grapgraph h is to is to be drawnbe drawn, , it must incluit must include the de the folfollolowinwing:g: titl

title, e, approprappropriate scales, iate scales, accuraaccurate plotting of te plotting of pointpoints, s, drawidrawing best ng best straigstraight line ht line (smoot(smoothh lines through exper

lines through experimentimental data points) and al data points) and labellabeling of ing of axes. axes. Slope calculSlope calculationations shoulds should be included after the graph.

be included after the graph. Each graph should conEach graph should convey a complete messagvey a complete message and e and be fullybe fully understandable without referring to any other section in the report.

understandable without referring to any other section in the report.

11. Error Analysis

This section must include the pertinent computed uncertainties (error estimates). It is This section must include the pertinent computed uncertainties (error estimates). It is im-portant here that the rule governing significant figures be used in computing and displaying portant here that the rule governing significant figures be used in computing and displaying these values.

these values.

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12. Discussion

This is the

This is the most importmost important part of ant part of your report, because here, you show that you your report, because here, you show that you understunderstandand the experiment beyond the simple level of completing it.

the experiment beyond the simple level of completing it. Expla Explain. in. AnalyAnalyse. se. InterpInterpret.ret. Some people like to think of this as the "subjective" part of the report. By that, they mean Some people like to think of this as the "subjective" part of the report. By that, they mean this is what is not readily observable. This part of the lab focuses on a question of this is what is not readily observable. This part of the lab focuses on a question of under-standing "What is the signiﬁcance or meaning of the results?" To answer this question, use standing "What is the signiﬁcance or meaning of the results?" To answer this question, use both aspects of discussion:

both aspects of discussion: Analysis

Analysis: : What do the resulWhat do the results indicats indicate clearlte clearly? y? What havWhat have you found? e you found? ExplaExplain whatin what you know with certainty based on your results and draw conclusions.

you know with certainty based on your results and draw conclusions. Interpretation

Interpretation: What is the signiﬁcance of the results? What ambiguities exist? What: What is the signiﬁcance of the results? What ambiguities exist? What questions might we raise? Find logical explanations for problems in the data.

questions might we raise? Find logical explanations for problems in the data. The experime

The experimental results should be compared with predicted valuental results should be compared with predicted values. s. If known valuesIf known values exist

exist, , the results shoulthe results should be d be comparcompared with these and a ed with these and a referencreference given (see belowe given (see below). ). Dis- Dis-crepancies should be considered in the light of the experimental error obtained and other crepancies should be considered in the light of the experimental error obtained and other random and systematic errors not

random and systematic errors not evevaluataluated numericalled numerically y in ‘Results’. in ‘Results’. If no If no knowknown n valvalue isue is av

availablailable, it e, it is still importanis still important to t to consiconsider all der all the possible errors. the possible errors. Then discuss the experi-Then discuss the experi-ment in general, its advantages and failings, procedural difﬁculties, ways of improving it ment in general, its advantages and failings, procedural difﬁculties, ways of improving it etc.

etc.

If any

If any questiquestions are asked ons are asked in the lab in the lab manualmanual, they should be , they should be answereanswered in d in this section of this section of the report.

the report.

13. 13. Final Results with Errors and Conclusio

Final Results with Errors and Conclusion

n

This should indicate how well the experiments have fulﬁlled the aims stated at the This should indicate how well the experiments have fulﬁlled the aims stated at the begin-nin

ning. g. SimSimply statply state what you know now for suree what you know now for sure, , as a as a resuresult of lt of the labthe lab, , and justand justify yourify your statement.

statement.

14. References

Any source of material used in the report should be listed here. Any source of material used in the report should be listed here.

Note:

Labs are always to follow this format except for planning and design labs. Labs are to be Labs are always to follow this format except for planning and design labs. Labs are to be communicated in a logical way using correct grammar and spelling.

communicated in a logical way using correct grammar and spelling.

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Chapter 1

Chapter 1 Lab #1: Electrostatics

Lab #1: Electrostatics

A leaf electrometer consists of an aluminum leaf which hangs at an angle

A leaf electrometer consists of an aluminum leaf which hangs at an angle θ θ _{to the vertical}_{to the vertical}

when a potential difference

when a potential difference V V _XY_XY_{is applied betweeen the metal cap}_{is applied betweeen the metal cap} X X _{and the conducting}_{and the conducting}

case

caseY Y _{of the electrometer.}_{of the electrometer.}

Figure 1.1: Leaf Electrometer Figure 1.1: Leaf Electrometer

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2

2 CHAPTER CHAPTER 1. 1. LAB LAB #1: #1: ELECTROSTELECTROSTAATICS TICS

It is calibrated by connecting different values of

It is calibrated by connecting different values of V V _XY_XY_across_across XY XY _{, with the following}_{, with the following}

results: results: V V _XY_XY

_//

V V ₁₁₀₀₀₀ ₂₂₀₀₀₀ ₃₃₀₀₀₀ ₄₄₀₀₀₀ ₅₀₅₀₀₀ ₆₀₆₀₀₀ ₇₇₀₀₀₀ ₈₈₀₀₀₀ ₉₉₀₀₀_{0 1}₁₀₀₀₀₀_{0 1}₁₁₁₀₀₀_{0 1}₁₂₂₀₀₀₀ θ θ

_//

◦◦ ₁₁₁₁ ₁₁₄₄ ₁₁₈₈ ₂₂₃₃ ₃₃₀₀ ₃₇₃₇ ₄₄₅₅ ₅₅₃₃ ₆₆₂₂ ₆₆₉₉ ₇₇₄₄ ₇₇₈₈ T Table able 1.1:1.1: a)

a) Plot a graph of Plot a graph of θ θ _against_againstV V _XY_XY_..

b)

b) The rate of change of The rate of change of θ θ _with_withV V _XY_XY_{is known as the sensitivity of the electrometer.}_{is known as the sensitivity of the electrometer.}

Over what range of potential differences is the sensitivity approximately constant? Over what range of potential differences is the sensitivity approximately constant?

Calculate the sensitivity over this range. Show all your working. Calculate the sensitivity over this range. Show all your working. c)

c) It is suggested that, between 300 It is suggested that, between 300V V _{and 700}_{and 700}V V _{, the potential difference is proportional to}_{, the potential difference is proportional to} sin

sin θ θ _..

Draw up a suitable table of values and plot a graph to test this suggestion. Does your graph Draw up a suitable table of values and plot a graph to test this suggestion. Does your graph support the suggestion?

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Chapter 2

Chapter 2 Lab #2 - ORR: Capacitance

Lab #2 - ORR: Capacitance

To determine a capacitance by measuring the time constant

of RC circuits

In this experiment you are to determine a capacitance by measuring the time constant of In this experiment you are to determine a capacitance by measuring the time constant of RC circuits.

RC circuits. Record all observaRecord all observations and deductiontions and deductions in s in your lab book.your lab book. a)

a) Connect the circuit shown in Figure 2.1 using a 10 Connect the circuit shown in Figure 2.1 using a 10 k _k Ω_Ω_{resistor for}_{resistor for R}_{R. Make sure that}_{. Make sure that}

both switches are open. both switches are open.

Figure 2.1: RC

Figure 2.1: RC CircuCircuitit 3

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4

4 CHAPTER 2. CHAPTER 2. LAB LAB #2 #2 - - ORR: ORR: CAPCAPACITACITANCE ANCE

Close switch

Close switch A A and wait for the voltmeter reading to reach and wait for the voltmeter reading to reach V V ₀₀_{, its}_{, its maxim}_{maximum value.}_{um value. Record}_Record V

V ₀₀_{and the value of}_{and the value of} S S _{, where}_{, where} S S

₌

₀₀

_..

₆₃₂₆₃₂V V ₀₀_..

Open

Open A A and close and close B B to discharge the capacitor. to discharge the capacitor. b)

b) The time constant The time constant τ τ _{of the circuit is equal to the time taken for the voltage to reach}_{of the circuit is equal to the time taken for the voltage to reach} S S

after switch

after switch AA is closed with the capacitor initially discharged and switch is closed with the capacitor initially discharged and switch BB open. open. Measure the time constant of the circuit as accurately as you can.

Measure the time constant of the circuit as accurately as you can. c)

c) Replace the 10 Replace the 10k k _Ω_Ω _{resistor with one of the other resistors and determine the new value}_{resistor with one of the other resistors and determine the new value}

for

for τ τ _{. . Repeat the procedu}_{Repeat the procedure until you have valu}_{re until you have values of}_{es of the time constan}_{the time constant for circuits}_{t for circuits}

containing each of the resistors provided. containing each of the resistors provided. Tabulate all your values of

Tabulate all your values of τ τ _and_and R_{R, the value of the resistance used.}_{, the value of the resistance used.}

d)

d) Use a graph page and plot a graph of Use a graph page and plot a graph of τ τ _/s_{/s (y-axis)}_{(y-axis) against}_against R_R /_/k _k Ω_Ω_(x-axis)._(x-axis).

Given that

Given that τ τ

₌

RC RC _{, use the graph to obtain a value for C, the capacitance of}_{, use the graph to obtain a value for C, the capacitance of C}_C..

e)

e) The resistaThe resistance values are quoted to a tolerance of 1%. nce values are quoted to a tolerance of 1%. State a range of values in whichState a range of values in which the true value of capacitance might lie. Show how you arrived at your answer.

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Chapter 3

Chapter 3 Lab #3 - ORR: Capacitor Discharge

Lab #3 - ORR: Capacitor Discharge

T

To

o in

inve

vest

stig

igat

atee th

thee ra

rate

te at

at wh

whic

ich

h a

a ca

capa

paci

cito

torr di

disc

scha

harg

rges

es th

thrrou

ough

gh

a

a voltm

voltmeter

eter

Part 1

(a)(i)

(a)(i) Co Connnnectect ththee cicircurcuitit shshowownn inin FiFig.g. 3.1. 3.1. YYouou shshououldld enensursuree ththatat ththee popoststiiveve (+(+)) tetermrmininalal of the power supply is connected to the + terminal of the capacitor

of the power supply is connected to the + terminal of the capacitor C C ₁₁_{(blue). Initially}_{(blue). Initially}

switch

switch S S _{should be closed.}_{should be closed.}

Figure 3.1: Capacitor Circuit Figure 3.1: Capacitor Circuit

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6

6 CHAPTCHAPTER ER 3. 3. LAB LAB #3 #3 - - ORR: ORR: CAPCAPACACITOITOR R DISCDISCHARGE HARGE

(ii)

(ii) Record Record the the inital inital readingreadingV V _o_o_{of the analogue voltmeter.}_{of the analogue voltmeter.}

((bb) ) ((ii)) Open switOpen switch S ch S and simultaneously and simultaneously start a start a stopwatch.stopwatch. (ii)

(ii) Measure and Measure and record values record values of the of the potential dipotential differencefferenceV V _{and time}_{and time} t t _until_until

the reading on the voltmeter becomes less than

the reading on the voltmeter becomes less than V V _o_o

_//

_10._10.

((cc) ) ((ii)) Plot Plot a a graph graph of of V V _{(y-axis) against}_{(y-axis) against} t t _(x-axis)._(x-axis).

(ii)

(ii) Use yoUse your grapur graph to h to determdetermine tine the tihe timeme τ τ _{for the potential difference across}_{for the potential difference across}

the capacitor to fall from

the capacitor to fall fromV V _o_o_to_to V V _o_o

_//

_5._5.

((dd) ) ((ii)) τ τ _and_andC C _{are related by the formula}_{are related by the formula} τ

τ

₌

CRCR_v_vlnln₅₅

where

where R R_v_v_{is the resistance of the voltmeter and}_{is the resistance of the voltmeter and} C

C _{is the capacitance of the capacitor}_{is the capacitance of the capacitor} C C ₁₁_..

Use your answer from

Use your answer from (c) (ii) (c) (ii) and the value of the capacitance C and the value of the capacitance C (written on the capacitor) to determine a value for

(written on the capacitor) to determine a value for R R_v_v_..

(ii)

(ii) Justify the Justify the number of signinumber of significant figures wficant figures which you hich you have gihave given forven for R R_v_v_..

Part 2

((ee) ) ((ii)) Connect Connect a a second second capacitorcapacitorC C ₂₂_{(yellow) in series with the ﬁrst capacitor}_{(yellow) in series with the ﬁrst capacitor} C C ₁₁_{(blue) so that}_{(blue) so that}

the circuit is now as shown in Fig. the circuit is now as shown in Fig. 3.23.2

Figure 3.2: Capacitor Series Circuit Figure 3.2: Capacitor Series Circuit

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7 7

(ii)

(ii) Repeat Repeat (b)(i) (b)(i) and and (b)(ii) (b)(ii)..

((ff) ) ((ii)) For the secFor the second set of resulond set of results and using tts and using the same set of axehe same set of axes as before,s as before, plot a graph of

plot a graph of V V _against_against t t _..

(ii)

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Chapter 4

Chapter 4 Lab #4 - ORR & MM: EMF and

Lab #4 - ORR & MM: EMF and

Internal Resistance

Apparatus

Dry cell, digital ammeter

(

00−−00

..

2020 A A

₎₎

_{whose resistance is known, decade resistance box,}_{whose resistance is known, decade resistance box,}

switch, connecting wires, switch, connecting wires,

metal ﬁlm resistors

(

11

..

11_k Ωk _Ω

_,,

₂₂

_..

₂₂k _k Ω_Ω

_,,

₃₃

_..

₃₃k _k Ω_Ω

_,,

₅₅

_..

₅₅k _k Ω_Ω

_,,

₁₀₁₀

_..

₀₀k _k Ω_Ω

_,,

₁₂₁₂

_..

₀₀k _k Ω_Ω

_,,

₁₅₁₅

_..

₀₀k _k Ω_Ω

_,,

₁₈₁₈

_..

₀₀k _k Ω_Ω

₎₎

_..

Figure 4.1:

Figure 4.1: CircuiCircuitt

Method

•

• ConnecConnect up the circuit as shown in the diagram, ﬁguret up the circuit as shown in the diagram, ﬁgure 4.1 4.1..

•

• Take 100 Take 100ΩΩout of the resistance box and, if the current is measurable on the ammeterout of the resistance box and, if the current is measurable on the ammeter

8 8

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9 9

scale record both the

scale record both the current and the resistance box reading.current and the resistance box reading.

•

• Gradually reduce the resistance of the box until the current has risen to about 0 Gradually reduce the resistance of the box until the current has risen to about 0

..

11 A A_..

Tabulate the results: Tabulate the results:

Resistance box Resistance box reading reading R R

₍

_Ω_Ω

₎₎

Ammeter reading Ammeter reading I I

₍

A A

₎₎

1

//

I I

₍

A A−−11

₎₎

T

Table able 4.1:4.1:

•

• Plot a graph with vPlot a graph with values of alues of R R

_//

_Ω_Ω_{as ordinates (y-axis) against the corresponding value}_{as ordinates (y-axis) against the corresponding value}

of

of _I_I11

((

A A−−11

₎₎

_{as abscissae (x-axis).}_{as abscissae (x-axis).}

Experimental Details

1.

1. The current throThe current through most resistaugh most resistance boxes should nence boxes should never exceever exceed about 0d about 0

..

11 A A_..

2.

2. BefBefore takinore taking g any readiany readings givngs give e all the plugs in all the plugs in the resisthe resistantance ce box a box a halhalf-tf-turn tourn to ensure that they are

ensure that they are properlproperly in.y in. 3.

3. If the resistance box possesses an inﬁnity plug it may be used instead of a circuit keIf the resistance box possesses an inﬁnity plug it may be used instead of a circuit keyy.. 4.

4. CheCheck the ck the ammammeteeter r for zero error and for zero error and if necessif necessary re-seary re-set t for zero readifor zero reading by ng by thethe adjusting screw provided.

adjusting screw provided.

Theory and

Theory and calculat

calculation

ion

Let

Let E E _represe_{represent the e.m.f.}_{nt the e.m.f. of the cell,}_{of the cell,}RR_C_C_{its internal resistance, supposed constant,}_{its internal resistance, supposed constant,} RR_the_the

resistance box reading,

resistance box reading, R R_A_A_the_{the resist}_{resistance of the}_{ance of the ammet}_{ammeter and}_{er and} I I _{the current in the circuit.}_{the current in the circuit.}

Then Then

E E R

(20)

10

10 CHAPTCHAPTER ER 4. 4. LAB LAB #4 #4 - - ORR ORR & & MM: MM: EMF EMF AND AND INTERINTERNANAL L RESISRESISTTANCE ANCE

Therefore, Therefore,

R

₌

E E _· ·



11 I

I −−

((

R RC C

+

R R A A

))



(4.2)

Hence, the graph of

Hence, the graph of R R

_//

_Ω_Ω_{(ordinates) against}_{(ordinates) against} 11

I

((

A A−−11

))

(abscissae) is a straight line whose (abscissae) is a straight line whose

slope is the magnitude of

slope is the magnitude of E E _{and whose negative intercept on the}_{and whose negative intercept on the} R R_{axis is the magnitude of}_{axis is the magnitude of}

((

R R_C_C

₊

R R_A_A

₎₎

_..

Measure the slope from the co-ordinates of two convenient points on the straight line. Measure the slope from the co-ordinates of two convenient points on the straight line. Produce the line to cut the axis of

Produce the line to cut the axis of RR_{and read off the inter}_{and read off the intercept}_{cept. . Sub}_Subtra_{tract the ammet}_{ct the ammeter}_er

resistance to ﬁnd the internal resistance

resistance to ﬁnd the internal resistance R R_C_C_{of the cell.}_{of the cell.}

Errors and accuracy

The error in

The error in RR_{may be neglected in comparison with the much larger possible error in}_{may be neglected in comparison with the much larger possible error in} I I

which depends on the range, sensitivity and scale markings of the ammeter used. From the which depends on the range, sensitivity and scale markings of the ammeter used. From the graph estimate the likely errors in

graph estimate the likely errors in E E _and_and R R_C_C_from_{from the differenc}_{the difference}_{e betwe}_{between the}_{en the valu}_{values found}_{es found}

from the chosen line and those obtained from other possible straight lines drawn through from the chosen line and those obtained from other possible straight lines drawn through the points (see the handout on Errors, Uncertainties & their Analysis).

(21)

Chapter 5

Chapter 5 Lab #5 - ORR: Determining the

Lab #5 - ORR: Determining the

resistance of a voltmeter

Apparatus

Analogue Voltmeter reading to 1.5 or 3V, two accumulators, 4 batteries with battery holder, Analogue Voltmeter reading to 1.5 or 3V, two accumulators, 4 batteries with battery holder, resistance box of total resistance not less than 1000

resistance box of total resistance not less than 1000ΩΩ, switch, leads with alligator clips,, switch, leads with alligator clips, metal ﬁlm resistors metal ﬁlm resistors

(

11k _k Ω_Ω

_,,

₁₁

_..

₅₅k _k Ω_Ω

_,,

₂₂

_..

₂₂k _k Ω_Ω

_,,

₃₃

_..

₃₃k _k Ω_Ω

_,,

₄₄

_..

₇₇k _k Ω_Ω

_,,

₅₅

_..

₅₅k _k Ω_Ω

_,,

₈₈k _k Ω_Ω

_,,

₉₉

_..

₄₄k _k Ω_Ω

₎₎

_.. Figure 5.1: Circuit Figure 5.1: Circuit

Method

•

• ConnecConnect up the t up the circuicircuit as shown in the diagram, ﬁguret as shown in the diagram, ﬁgure 5.1 5.1..

11 11

(22)

12

12CHCHAPAPTETERR 5. 5. LALABB #5#5 -- ORORR:R: DEDETETERMRMININININGG THTHEE RERESISISTSTANANCECE OFOF AA VVOLOLTMTMETETERER

•

• Take out a large resistance from the resistance box Take out a large resistance from the resistance box RR_{and note whether any reading}_{and note whether any reading}

is obtaine

is obtained on the voltmeted on the voltmeter scale. r scale. DecreaDecreasese RR_{until the voltmeter reading is at its}_{until the voltmeter reading is at its}

maxim

maximum on um on the scale. the scale. Record the resistanceRecord the resistance R R_{and the voltmeter reading}_{and the voltmeter reading}V V _..

•

• Increase Increase RR_in_{in sui}_suitab_{table steps to}_{le steps to mak}_make_{e ful}_full_{l use of}_{use of the volt}_{the voltmet}_meter_{er scal}_scale._{e. T}_Tab_abula_{ulate the}_{te the}

results: results: Resistance box Resistance box reading reading R R

₍

_Ω_Ω

₎₎

Voltmeter Voltmeter reading readingV V

₍₍

V V

₎₎

1 1

//

V V

₍₍

V V −−11

₎₎

T Table able 5.1:5.1: •

• Plot a graph with Plot a graph with values of values of R R

_//

_Ω_Ω_{as ordinates (y-axis) against the corresponding value}_{as ordinates (y-axis) against the corresponding value}

of

of _V_V11

((

V V −−11

₎₎

_{as abscissae (x-axis).}_{as abscissae (x-axis).}

Experimental Details

1.

1. The current throThe current through most resistaugh most resistance boxes shoulnce boxes should never exceed never exceed about 0d about 0

..

11 A A_..

2.

2. BefBefore takinore taking g any readany readingings s gigive all ve all the plugthe plugs s in the in the resiresistastance box nce box a a halhalf-tuf-turn torn to ensure that they are

ensure that they are properlproperly in.y in. 3.

3. If the resistancIf the resistance box possesses an inﬁnity plue box possesses an inﬁnity plug it may be g it may be used insteaused instead of a d of a circuicircuit keyt key.. 4.

4. CheCheck the ck the ammammeteeter r for zero error and for zero error and if necessif necessary re-seary re-set t for zero readifor zero reading by ng by thethe adjusting screw provided.

adjusting screw provided.

Theory and

Theory and calcula

calculation

tion

Let

Let E E _represe_{represent the total e.m.f.}_{nt the total e.m.f. of the circuit,}_{of the circuit,} R R_{the resistance box reading,}_{the resistance box reading,}V V _{the voltmeter}_{the voltmeter}

reading, and

(23)

13 13

Then the current

Then the current I I _{in the circuit is}_{in the circuit is}

I

₌

E E R

R

₊

R R_V_V (5.1)(5.1)

assuming the resistance of the accumulators in the circuit to be negligible. assuming the resistance of the accumulators in the circuit to be negligible. Hence, the voltage across the voltmeter is

Hence, the voltage across the voltmeter is

V

₌

I I RR_V_V

₌

E E R R

₊

R R_V_V ·· R RV V (5.2)(5.2) Rearranging, Rearranging, R R

₊

R R_V_V

₌

E E RR_V_V_· · 11 V V (5.3)(5.3) or or R R

₌

E E RR_V_V_· · 11 V V −− R RV V (5.4)(5.4)

Thus, the graph of

Thus, the graph of R R

_//

_Ω_Ω_{(ordinates) against}_{(ordinates) against} 11

V

((

V V −−11

))

(abscissae) is a straight line whose (abscissae) is a straight line whose

negative intercept on the

negative intercept on the R R_{axis is the magnitude of}_{axis is the magnitude of} R R_V_V_..

Errors and accuracy

The error in

The error in RR_{may be neglected in comparison with the much larger possible error in}_{may be neglected in comparison with the much larger possible error in} V V

which depend

which depends on s on the range, sensitithe range, sensitivity and scale markings of the voltmetvity and scale markings of the voltmeter used. er used. FromFrom the graph estimate the likely errors in

the graph estimate the likely errors in RR_V_V_{from the difference between the values found}_{from the difference between the values found}

from the chosen line and those obtained from other possible straight lines drawn through from the chosen line and those obtained from other possible straight lines drawn through the points (see the handout on Errors, Uncertainties & their Analysis).

(24)

Chapter 6

Chapter 6 Lab #6 - A&I: Resistance per unit length

Lab #6 - A&I: Resistance per unit length

of wire D

Apparatus

1.5V dry cell, analogue ammeter, connecting wires with alligator clips, switch, meter rule, 1.5V dry cell, analogue ammeter, connecting wires with alligator clips, switch, meter rule, 100cm length of wire (wire B), and 15cm length of wire (wire D).

100cm length of wire (wire B), and 15cm length of wire (wire D).

Figure 6.1:

Figure 6.1: CircuiCircuitt

In this experiment you will use a wire (labelled

In this experiment you will use a wire (labelled B B) of known resistance per unit length) of known resistance per unit length (which should be taken to be 4

(which should be taken to be 4

..

0000ΩΩmm−−11_{) to ﬁnd the combined resistance of a cell and an}_{) to ﬁnd the combined resistance of a cell and an}

ammet

ammeterer. . YYou will use this value to ﬁnd ou will use this value to ﬁnd the resistanthe resistance per ce per unit lengtunit length of h of a second wirea second wire (labelled

(labelled D D).).

14 14

(25)

15 15

Procedure

(a)

(a) Set up the circuiSet up the circuit of ﬁguret of ﬁgure 6.1 6.1.. (b)

(b) For different lengths of wire For different lengths of wire B B in the circuit, record the following quantities in a table in the circuit, record the following quantities in a table

S

S _{the scal}_{the scale readi}_{e reading of th}_{ng of the current}_{e current as sho}_{as shown on t}_{wn on the amm}_{he ammeter}_eter,, b

b _the_{the lengt}_length_{h of}_{of wire}_wire B_B used,_used, R

R_b_b _{the r}_{the resista}_{esistance of}_{nce of lengt}_{length b}_{h b of wi}_{of wire}_re B_{B, and}_{, and}

1 1

//

S S

(c)

(c) Insert 15 Insert 15

..

00cmcm_{of wire}_{of wire D}_{D between the switch and the cell.}_{between the switch and the cell. Repeat the procedu}_{Repeat the procedure of}_{re of}

part (b), record your readings in your table. part (b), record your readings in your table. (d)

(d) Both graphs are of the form Both graphs are of the form

R

R_b_b

₌

k k 1 1 S

S −−r r (6.1)(6.1)

where

where k k _{is a constant, and}_{is a constant, and} r r _{is the resistance of the other components of the circuit used.}_{is the resistance of the other components of the circuit used.}

•

• Plot graphs of your values from (b) and (c). For your graphs, use the same axes and Plot graphs of your values from (b) and (c). For your graphs, use the same axes and scales, extending the

scales, extending the R R

_//

_Ω_Ω _{axis to include}_{axis to include} R R

_//

_Ω_Ω

₌

₋₋_2._2.

(e)

(e) Deduce from the graphs vaDeduce from the graphs values forlues for (i)

(i) the combined resistance of the cell and ammeter, the combined resistance of the cell and ammeter, (ii)

(ii) the resistance of the length of wire the resistance of the length of wire D D used in (c). used in (c). Hence calcuHence calculate the resistalate the resistance pernce per unit length of wire

unit length of wire D D..

(You may assume that the circuit leads have negligible resistance.) (You may assume that the circuit leads have negligible resistance.)

(26)

Chapter 7

Chapter 7 Lab #7 - P&D: P.D. and I relationship

Lab #7 - P&D: P.D. and I relationship

across a ﬁlament

Objective

In this experiment you will investigate the relationship between the potential difference In this experiment you will investigate the relationship between the potential difference across a ﬁlament and the current in it.

across a ﬁlament and the current in it.

Instructions

Choosing from the apparatus provided, set up a circuit to enable you to investigate the Choosing from the apparatus provided, set up a circuit to enable you to investigate the relationship

relationship

V

V ∝∝ I I nn _(7.1)_(7.1)

where

whereV V

₌

_{the p.d.}_{the p.d. across the ﬁlament lam}_{across the ﬁlament lamp,}_p, I

I

₌

_{the current in the ﬁlament}_{the current in the ﬁlament}

and

and nn_{is a constant, the value of which you are to determine.}_{is a constant, the value of which you are to determine.}

16 16

capephysics labs2 v4

BISHOP ANSTEY HIGH SCHOOL EAST AND

BISHOP ANSTEY HIGH SCHOOL EAST AND

TRINITY COLLEGE EAST (BATCE)

TRINITY COLLEGE EAST (BATCE)

Sixth Form

Sixth Form

CENTRE NO. 160570

CENTRE NO. 160570

CXC CAPE Physics

CXC CAPE Physics

Unit 2 Lab Manual

Unit 2 Lab Manual

2015-2016

2015-2016

cc





Copyright by Bishop Anstey High School East and Trinity College East

Copyright by Bishop Anstey High School East and Trinity College East

(BATCE) 2015

(BATCE) 2015

All Rights Reserved

All Rights Reserved

Rules and Regulations of the Laboratory

Rules and Regulations of the Laboratory

Policy Principles

Policy Principles

Format for Written Reports

Format for Written Reports

0. Cover Sheet

0. Cover Sheet

1. Title

1. Title

2. Aim/Objective(s)

2. Aim/Objective(s)

3. Theory/ Introduction

3. Theory/ Introduction

4. Apparatus

4. Apparatus

5. Diagram

5. Diagram

6. Method/ Procedure/ Experimental Details

6. Method/ Procedure/ Experimental Details

7. Precautions & Sources of Error

7. Precautions & Sources of Error

8. Results

8. Results

9.

9. Sample Calcul

Sample Calculations

ations

10. General Analysis

10. General Analysis

11. Error Analysis

11. Error Analysis

12. Discussion

12. Discussion

13.

13. Final Results with Errors and Conclusio

Final Results with Errors and Conclusion

n

14. References

14. References

Note:

Note:

Contents

Contents

Chapter 1

Chapter 1

Lab #1: Electrostatics

Lab #1: Electrostatics

//

//

Chapter 2

Chapter 2

Lab #2 - ORR: Capacitance

Lab #2 - ORR: Capacitance

To determine a capacitance by measuring the time constant

To determine a capacitance by measuring the time constant

_//

_//

₌

₌

_..

₌

₌

_//

_//

₌

₌

₎₎

_,,

_..

_,,

_..