Q1.State five properties of X-rays
Q2.State five properties of X-rays
Q3.Physics KCSE 2020 Paper 1 Qs 1-2
1. The radius of a wire was measured as 2.43mm. Name the instrument that is used to measures this diameter
Micrometer Screw Gauge
2. Figure 1 shows a capillary tube dipped in mercury in a beaker. State with a reason the observation that would be made on the level of mercury in the capillary tube if the temperature of the mercury is increased
The level rises – cohesive forces become weaker on heating
Q4.KCSE 2020 Paper 1 Qs. 3-4
3. State the kinetic theory of gases.
It states that gases are made up of tiny molecules that are in constant random motion
4. Figure 2 shows the scale of a measuring instrument.
a. Determine the reading indicated
b. State the physical quantity measured in this instrument
Q5.Physics Paper 1 KCSE 2020 Qs. 5
5. Figure 3 shows a traditional stool resting on a level surface.
a. Identify its state of equilibrium
b. State the reason for your answer in a
Q6.KCSE Paper 1 2020 Physics
6. Figure 4 shows a uniform rod AB of length 1m and weigh 8N pivoted at 20cm from one end. It is balanced by supporting it with a string attached to a fixed support. The tension in the string is 4N. Determine the position of the string from end A
4 x x = 8 x 30
4x = 240
Position of string = 60 + 20 =80cm
Q7.KCSE Physics Paper 1 2020 Q 7-9
7. Define cohesive forces
Forces of attraction between molecules of the same type
8. Two similar containers A and B are filled with equal masses of water at the same temperature. Container A is made up of copper while B is made up of glass. Heat is then supplied to the containers at the same rate. State with a reason the container in which water boils first 2mks
Container A. It is a better conductor of heat.
9. Figure 5 show a roof of a house over which wind is blowing. It was observed that when the speed of wind is increased, the roof is blown off. Explain this observation 2mks
Q8.KCSE 2020 Physics Paper 1
10.Figure 6 shows the velocity time graph of the motion of a stone thrown vertically upwards. From the graph determine the height reached by the stone 3mks
Displacement = Area under the graph (the curve)
= ½ x 2 x 20 =20m
Q9.KCSE 2020 Physics 1 Qs. 11-12
11. It is observed that when methylated spirit is poured on the palm, the palm feels colder as it dries up. Explain this observation.
12. Figure 7 shows a box on a weighing balance. The balanced is placed on the floor of a lift.
State what would be observed on reading the balance when ;
a. Lift is accelerating downwards
b. Lift moves downwards with a uniform velocity
c. Lift is accelerating upwards
Q10.KCSE Physics Paper 1 Q13-14
13. An object is placed on the surface of water in a beaker start to sink immediately. It is observed that it stopped sinking when half of its volume is below the water surface. State the reason for this observation
As it sinks upthrust increases, and stops when upthrust is equal to the weight of the object
Section B (55mks)
14. (a) Figure 8 shows a bucket full of water and tied to one end of the string which is used to whirl it in a vertical circular path with a uniform speed V
i. State two forces acting on the bucket at any instant 2mks
Weight of the bucket
Tension on string
ii. Explain why tension is lowest at point A 2mks
Part of the centripetal force required is provided by the weight. Tension and weight act in the same direction therefore tension will be less
iii. The speed of the bucket is gradually reduced. Explain what is likely to be observed when the bucket is at point A
Water is likely to pour out.
At certain minimum speed the centripetal force is less than what is required to keep the motion of the bucket therefore some water spill out (T=0)
(b) A mass of 40kg is whirled at the end of a string in a circular horizontal at a speed of 12ms-1. (The stone and the string are in the same horizontal place). If the string is 1m long, determine the tension in the string
Q11.KCSE 2020 Physics Paper 1 Q15(a)
15 (a) Figure 9 shows a set-up used by a student to investigate how a siphon works.
(i) State what will be observed when the student sucks the tube at point A and release it 2mks
Upon sucking, the liquid flows in the delivery tube but stops on releasing because the sucking force is withdrawn
(ii) Explain the observation in a(i) 2mks
The liquid fails to flow on release because there is no pressure difference to push the liquid up the tube without sucking, the level of the container is above the liquid level