SOTIK DISTRICT PHYSICS PRACTICAL QUESTIONS AND ANSWERS

SOTIK DISTRICT PHYSICS PRACTICAL QUESTIONS

1.  You are provided with the following apparatus:-

• Micrometer screw gauge
  
• Vernier caliper
  
• Water in a beaker 1000ml(should be ½ full)
  
• Long test-tube
  
• Some dry sand
  
• Spatula
  
• Millimetre scale marked on a paper strip
  
• Some cellotape
  
• 6 ball bearings
  

Proceed as follows:-

(i) Measure and record the diameter d of one ball bearing using micrometer screw gauge

  d = ____________________cm

(ii) Determine the volume V of the spherical ball bearing

 V = ___________________cm³

(iii) Measure the inside diameter d of the test-tube using vernier caliper. Record it below:

  d = __________________cm

(iv) Find the cross-section area A of the test tube

  A = ____________ cm²

(b) (i) Place the millimeter scale along the height of the test tube so that the zero is at the bottom

  (ii) Place the test-tube in the water carefully and add sand bit by bit until it floats while

vertically upright in the water as shown:-

(iii) Note and record the height h_o
of water level by use of attached millimeter scale

h_o = ______________cm

(c) Add one ball bearing into the tube, note and record the new level h in the table of results below:

(d) Repeat step (c) with two, three, four, five & six ball bearings and record their corresponding h(cm).

Compute values of h-h_o(cm) in the table below:-

(e) Plot a graph of h-h_o(cm) against the number of ball bearings (N)  

(f) Determine the slope S, of the graph

(g) Relative density P_s, of ball bearing is given by:

P_s = SA. Find P_s  

V

2. PART I  

You are provided with the following apparatus:-

• Rectangular glass block
• Four optical pins  
• Plain paper
• Soft board
• Piece of cellotape  

Proceed as follows:-  

(a) (i) Use cellotape provided to hold the sheet of plain paper on the soft board

(ii) Place the glass block on the middle of plain paper and with a sharp pencil, draw its outline

ABCD as shown:-

1. (i) Construct the normal on side AB, but close to A. Use protractor and ruler to draw an  

incident ray with an angle of incidence = 10^o   (ii) Insert pins P₁ and P₂ along the path drawn. Viewing through the glass block on side CD,

 locate P₃ and P₄ such that P₃ P₄ appear in line with images of P₁ and P₂  

(iii) Produce P₁P₂ to obtain a lateral displacement as shown in the figure below:-

Measure angle of refraction r, and lateral displacement

 (c) Repeat steps (b)(ii) and (b)(iii) for angles of incidence i = 20^o, 30^o, 40^o, 50^o and 60^o. Tabulate   your results as shown in the table:- Note: (You must handover your workings on the plain paper with the question paper after the session)

(d) Plot a graph of lateral displacement, d, against angle of refraction r

2.  PART II

You are provided with the following:-

• An ammeter (0- 1A)  
  
• A voltmeter (0-2.5V or 0-5V)
  
• Two dry cells
  
• A mounted resistance wire
  
• Eight connecting wires, two with crocodile clips
  
• A three volts torch bulb in a bulb holder
  
• A cell holder
  
• A switch
  
• A jockey or a crocodile clip

(a) Set-up the apparatus as shown below:-

(b) With the jockey or crocodile clip at C, 30cm, 50cm and 70cm, record their corresponding

V₁, V₂ and V₃

(c) Replace the voltmeter with a torch bulb and an ammeter. Connect in series as shown in the

circuit diagram:-  

(d) Read and record the ammeter reading I₁, I₂ and I₃ for the corresponding values of lengths:

ℓ₁ = 30cm, I₁ = _______________

ℓ₂= 50cm, I₁ = __________________  

ℓ₃= 70cm , I₃ = ___________________  

(e) (i) Determine voltage values across the bulb for lengths 30cm, 50cm and 70cm given that

V = 0.025L

(ii) Determine the average resistance of bulb during the experiment  

SOTIK DISTRICT PHYSICS PRACTICAL ANSWERS

1.  (i) d = 0.635cm 0.05

(ii) V = ⁴/₃ (0.635)³ = 0.134cm³ 0.13 allow 0.14

(iii) d = 1.68 0.01

(iv) A = r² = 3.14 x (1.68)² = 2.21 (2.21 – 2.30)

=

(b) (iii) h_o = 8.6cm ±0.2cm 8.0

(d)

(1mk for mark for each h value upto a max. of 4mks )

1mk for atleast 5 correct differences

½ mk for 3 and 4 correct differences

2 or less correct differences 0mks

(e) Axes – must be labeled the units (mark both)

Scale – be simple & uniform *

Plotting = ½ mk for each correctly plotted points up to 2mks

> 4 correct plotted 2mks

> 2 & 3 correctly plotted 1mk

<2 correctly plotted 0mk

Line must pass at least 3 correctly plotted points  

(f) S = 0.527cm – Identifying the pts on the graph

-Correct substitution ( ½ mk)

-Correct answer to 2d.p ( ½ mk)

(g) O_s = 0.527 x 2.21 (correct sub

0.134

= 8.69 ( no units) (correct evaluation to 2d.p –

2. PART 1  

(c)

½ mk for each correct value of both r and d

(d)

• Axes (Quantity and units- 1mk)
  
• Scale (simple and uniform 1mk)
  
• Plotting ( ½ mk for each correctly plotted point up to 2mks)  
  
• The graph’s curve as shown
  
• Maximum = 6mks  
  
• Smooth curve with correct shape as shown 1mk
  

Note:- The workings on the plain paper must be seen before marking this section

2. Part II

(b) ₁ = 30cm, V₁ = 0.75 ± 0.05

₂ = 50cm, V₂ = 1.225  

₃ = 70cm , V₃ = 1.75  

(d) ₁ = 30cm , I = 0.12A ± 0.01

₂ = 50cm ₂ = 0.16A

₃ = 70cm F₃ = 0.20A*STK*

e(i) V₁ = 30 x 0.0025 = 0.75V

V₂ = 50 x 0.025 = 1.25V

V₃ = 70 x 0.025 = 1.75

3values of V correctly calculated 1mk

2 values of V correctly calculated ½ mk

0.01 value of V correctly calculated 0mk

(ii) R₁ = V₁ = 0.75 = 6.25

I₁ 0.12

R₂ = V₂ = 1.25 = 7.81

I₂ 0.16

R₃ = V₃ = 1.75 = 8.75  

I₃ 0.2

3 values correctly calculated to 2d.p 1mk

2 values correctly calculated to 2d.p ½ mk

0 or 1 value correctly calculated to 2d.p 1mk 0mk

Average R = R₁ + R₂ + R₃
= 6.25 + 7.85 + 8.75 = 22.85 = 7.617  

3 3 3

Substitution of 3 values of R ½ mk

Correct evlauation of average R value to 3d.p ½ mk