##### Search ### KCSE CLUSTER TESTS 16

#### Physics Paper 3

1.

Part I

You are provided with the following apparatus

 A Small syringe

 A 10cm strip of cello tape.

 A 30cm long piece of thread

 A half meter rule

 A stand, boss and clamp

 A beaker with water

a) i) Measure and record the width of (w) of the cello tape provided.

W= _________________________________cm

ii) Using the thread provided wind 5 turns round the syringe and determine its circumference. (πD)

πD= _______________________________cm

iii) Determine the radius, (r) of the syringe.

r= ________________________________

iv) Wind the cello tape around the syringe approximately 1cm from the lower side as shown in the diagram below. Determine the volume of the part of the syringe covered by the cello tape using the relationship

(πr2w)= _________________________cm3

b) i) Fill the syringe with water and its outlet in an upward position; tap the syringe gently with the finger to remove air bubbles. Clamp the syringe vertically and push down the piston until the bottom of the piston is in level with the top of the cello tape. Now count the number of the water drops that fall from the syringe into the beaker as you push the piston slowly to the bottom of the cello tape. The number, n, of the drops of water. N=________________________________cm3

ii) Determine the average volume, v, of one drop of water

V= _______________________cm3

Part II

You are provided with the following:

 A wooden block with a hook

 A set of masses

 A string

 A balance and pulley

Proceed as follows: i) Determine the mass of the rectangular wooden block using the balance provided.

Mass of block = ___________________________________g.

ii) Tie one end of the string / thread to a hook of the block and the other end to a 50g mass as shown on the figure 2 above. Adjust the string over a properly arranged pulley. Take care that the position of the string in between the block and pulley is exactly parallel to the table top. The wooden block should rest on a plane paper fixed on the table top.

iii) Place a weight of 100g on the block and add the weights on the 50g mass hanging such that the block just tends to move.

iv) The weight of the block plus the weights placed on it is denoted by R while the weight of the 50g mass holder plus the weight added on it is denoted by F.

v) Use different weights of 200g, 300g,400g, 500g and 600g on the block and determined the corresponding value of F for each one of them. Record your values in the table below: vi) On the grid provided plot a graph of F(y-axis) against R. vii) Determine the slope (S) of the graph

S=

viii) What is the significance of the slope you have determined in the above question?

20 marks

2.

Part I

You are provided with

 Two new dry cells.

 Ammeter

 Cell holder

 Switch

 Voltmeter

 Six connecting wires, atleast 2 with crocodile clips.

 Jockey

 Nichrome wire mounted on a millimeter

Scale labeled XY

Proceed as follows

a) Set –up the circuit as shown in the figure below. b) With the switch open measure the e.m.f, E of the cell.

E____________________________V

c) Close the switch and with L =10cm measure and record ammeter and voltmeter reading.

d) Repeat the above procedure for L= 20cm, 30cm, 40cm, 70cm and 100cm hence fill the table below e) i) Plot a graph of E- V (y –axis) against current ii) Determine the slope of your graph.

Given that the equation of the graph is E = V+Ir, determine r the internal resistance

Part II

You are provided with the following apparatus

 Meter rule

 White screen

 Candle

 Lens

 Lens holder

 Converging lens

Proceed as follows

a) Place the lens on the lens holder. Ensure that the height of the lit candle is in line with the axis of the lens on the lens holder. Arrange the apparatus such that the distance L between the object and the screen is 50cm. b) Adjust the lens so that an enlarged image is formed on the screen at A and mark point A.

c) Without altering length L, move the lens to a position such that a diminished sharp image is formed on the screen and mark this point B.

d) Measure distance d, between A and B

d_________________________________________cm 20 marks

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