In an elastic collision, momentum is conserved as well as well as?

• A. velocity
• B. kinetic energy
• C. potential energy
• D. speed

The focal length of a concave mirror is 2.0cm. If an object is placed 8.0cm from it, the image is at

• A. 2.7m
• B. 2.0m
• C. 2.3m
• D. 2.5m

A lamp marked 100W, 250V is lit for 10 hours. If it operates normally and 1KWh of electrical energy costs 2k, what is the cost of lighting the lamp?

• A. 1k
• B. 2k
• C. 5k
• D. 10k

A satellite revolving around the earth is kept on its orbit by

• A. Centripetal forces only
• B. Centripetal and frictional forces
• C. Centrifugal forces only
• D. Centripetal and centrifugal forces

A force of 20 N applied parallel to the surface of a horizontal table, is just sufficient to make a block of mass 4kg move on the table. Calculate the coefficient of friction between the block and the table. (g = 10ms^-2)

• A. 0.05
• B. 0.20
• C. 0.50
• D. 0.80

Two identical cups containing the same volume of water at 45°C and 5°C, are left in a room at 25°. Which of the following graphs correctly illustrates the variation of temperature with time?

• A. A
• B. B
• C. C
• D. D

A ball is projected horizontally from the top of a hill with a velocity of 20m^-1. If it reaches the ground 4 seconds later, what is the height of the hill? (g = 10ms^-2)

• A. 20m
• B. 40m
• C. 80m
• D. 160m

A 5kg block is released from rest on a smooth plane inclined at an angle of 30^o to the horizontal. What is the acceleration down the plane? [g = 10ms^-2]

• A. 5.0 ms^-2
• B. 5.8 ms^-2
• C. 8.7 ms^-2
• D. 25.0 ms^-2

It takes 4 minutes to boil a quantity of water using an electrical heating coil. How long will it take to boil the same quantity of water using the same coil if the current is doubled? [Neglect any external heat losses]

• A. 8 minutes
• B. 4 minutes
• C. 2 minutes
• D. 1 minute

A stone is dropped into the middle of a pool of water. Which of the following statements is/are correct? I, Spherical waves are set up in the water. II. The water moves outwards to the sides of the pool. III. Energy is transmitted outwards from the centre of disturbance

• A. I only
• B. II only
• C. III only
• D. I and III only