P510/3 PRACTICAL PHYSICS Paper 32019 3 ¼ hours

Uganda Advanced Certificate of Education.

PRACTICAL PHYSICS

Paper 3

3 hours: 15 minutes

INSTRUCTIONS TO CANDIDATES

Answer Question 1 and one other question

Any additional question(s) will not be marked

Candidates are not allowed to use the apparatus for the first fifteen minutes

Graph paper is provided

Mathematical tables and non programmable scientific electronic calculators may be used

Candidates are expected to record all their observations as they are made and plan the presentation of the records so that it is not necessary to make a fair copy of them.

The working of the answers is to be handed in.

Details on the question paper should not be repeated in the answer, nor is the theory of the experiment required unless specifically asked for. However, candidates should record any special precautions they have taken and any particular feature of their methods of going about the experiment.

Marks are given mainly for a clear record of the observations actually made, for their suitability and accuracy and for the use made of them.

For each question, candidates will be required to select a suitable apparatus from the equipment provided.

Turn Over

1. In this experiment you will determine the radius of gyration k of metre rule provided using two methods. (34 marks)

METHOD 1a) Clamp metre rule labeled B at a height of 50.0cm above the table such that the

graduated face is towards you.

b) Suspend metre rule labeled A from the clamped metre rule by means of two vertical threads such that the graduated face is upwards as shown in figure 1.

c) Adjust the length l to 0.500m.

d) Adjust the distance x to 4.00m.

e) Displace the ends of metre rule labeled A to perform small horizontal oscillations about the vertical axis.

f) Measure and record the time t, for 20 oscillations.

g) Repeat procedures (d) to (f) for values of x = 0.350, 0.300, 0.250, 0.200, and 0.150m.

h) Tabulate your results including values of period T and 1x

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i) Plot a graph of T against 1x

j) Find the slope S0 of the graph.

k) calculate the value of K1 from the expression.

K1So

2 π √ gt

Where π = 3.14

g = 9.81ms-2

METHOD IIa) Use the knife edge provided to determine the centre of gravity G of the metre rule

labeled A.

b) Measure and record the distance h from G to the hole H.

c) Using the pieces of wood clamp the optical pin horizontally.

d) Suspend metre rule labeled A from hole H as shown in figure 2.

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e) Displace the metre rule labeled A slightly so that it oscillates.

f) Measure and record the time t0 for 20 oscillations.

g) Calculate the period T0.

h) Calculate the value K2 from the expression.

K 2= 12 π √h (T 0

2 g−4 π2h)

Where; g = 9.81ms2 π = 3.14

i) Calculate the value of K form the expression.

K =( K1+ K2 )

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2. In this experiment you will determine the refractive index,∩, of the material of the glass block provided using three methods. (33 marks)

METHOD 1

a) Fix the plain white sheet of paper on the soft board using drawing pins.

b) Place the glass block in the middle of the plain white sheet of paper with the broadest face upwards and trace its outline PQRS.

c) Draw a normal NM at B such that PB = 2.0cm.

d) Draw a line AB such that the angle I = 400 as shown in figure 3.

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e) Draw a line TU, 20.0cm long and parallel to SR and 5.0cm from SR.

f) Put back the glass block on its outline.

g) Fix optical pins P1 and P2 vertically on the line AB.

h) While looking through the glass block from side SR, fix optical pins P3 and P4

such that they appear to be in line with the images of P1 and P2.

i) Remove the glass block and the optical pin.

j) Draw a line through P3 and P4 to meet SR at C and TU at D.

k) Draw a normal to SR at C.

l) Measure and record the length y, of CD and angle a.

m) Calculate the value of ∩1 from the expression

∩1= ( y2−x2 )12

y sin a

Where; x = 5.0cm

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METHOD II and IIIa) Measure and record the width w of the glass block.

b) Fix a fresh plain white sheet of paper on the soft board using drawing pins.

c) Place the glass block in the middle of the plain sheet of paper with the broadest face upwards and trace its outline ABCD.

d) Remove the glass block.

e) Draw a normal NQ at Q where DQ = 14

( DC )

f) Draw a line OQ such that angle i = 200 as shown in figure 4.

g) Fix two optical pins P1 and P2 on the line OQ.

h) While looking through the glass block from side AB, fix optical pins P3 and P4

such that they appear to be in the images of P1 and P2.

i) Remove the glass block and the optical pins.

j) Draw a line through P3 and P4 to meet AB at R.

k) Join K to Q.

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l) Measure and record the length, l of KQ.

m) Repeat the procedures (f) to (I) for values of i=300,400,500,600 and 700.

n) Tabulate your results including values of sin2 i and 1t2

o) Plot a graph sin2 i against 1t2

p) Find the slope S of the graph.

q) Read and record the intercept C of the sin2 i axis.

r) Calculate the value of ∩2 from the expression.

∩2=√−sW 2

s) Calculate the value of ∩3 from the expression;

∩=[∩1+∩2

2 ]KEEP YOUR TRACINGS FOR HANDING IN

PART 13. In this experiment you will determine the resistance per metre∅ of the wire labeled

W.a) Connect the circuit shown in figure 5.

b) Adjust the length L to 0.200m

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c) Close switch K

d) Read and record the voltmeter reading V1 and ammeter reading I1

e) Open switch K

f) Adjust the length L to 0.400m

g) Close switch K

h) Read and record the voltmeter reading V2 and ammeter reading I2

i) Open switch K

j) Calculate the value of ∅ from the expression.

∅= ½ [2 V 2

I 1+

4 V 2

3 I 2 ]PART II

In this experiment you will determine the resistivity ρ and constant r of the wire

labeled w.

a) Measure and record the diameter, d of the wire labeled w.

b) Connect the circuit shown in figure 6.

c) While switch K2 is open close switch K1

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d) Move the jockey along the potentiometer slide wire AB to locate the point D where the galvanometer shows no deflection.

e) Read and record balance length l0

f) Open switch K1

g) Adjust the length y of the wire labeled w to 0.20m

h) Close switches K1 and K2. Move the jockey along the potentiometer wire AB to locate the point D where the galvanometer shows no deflection.

i) Read and record the balance length l.

j) Repeat procedures (g) to (i) for values of y = 0.300, 0.400, 0.500, 0.600 and 0.700m.

k) Tabulate your results including values of t = ti0−i

l) Plot a graph of y against t

m) Find the slope ∝ of the graph.

n) Calculate the value of ρ from the expression

ρ=πd2∅4

o) Calculate the value of r from the expression.

R=a∅

END

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