The time rate of increase in velocity is called

• A. force
• B. momentum
• C. acceleration
• D. speed

Which of the following devices is used to compare the relative magnitudes of charges on two given bodies?

• A. Ebonite rod
• B. Proof Plane
• C. Gold Leaf Electroscope
• D. Electrophorus

which of the following materials is a conductor?

• A. Glass
• B. Wax
• C. Sodium
• D. Plastic

Which of the following affects the period of a simple pendulum? i. mass of the pendulum bob. ii. length of the pendulum. iii. acceleration due to gravity.

• A. i, ii, and iii
• B. ii and iii only
• C. i and iii only
• D. i and ii only

The amplitude of a sound wave determines its

• A. frequency
• B. quality
• C. loudness
• D. pitch

Which of the following statements is true of ultra violet radiations? It

• A. supports the sensation of hearing
• B. does not cause the emission of electrons from metals
• C. is an electromagnetic wave
• D. is not capable of causing sun burns

A magnetic field is said to exist at a point if a force is

• A. exerted on a stationary charge at the point
• B. exerted on a moving charge at the point
• C. deflected at the point
• D. strengthened at the point

A solid body will float in a liquid if its

• A. density is less than that of a liquid
• B. mass is equal to that of the liquid
• C. density is greater than that of the liquid
• D. mass is less than that of the liquid

A ball bearing falls through a viscous liquid

(a) Using a labelled diagram of a tall vessel, show all the forces acting on it

(b) When will it attain terminal velocity?

A rotating disc contains a set of holes in a circle. An air jet is directed onto the holes and a note of frequency 480 Hz is produced. If the number of holes is 20, calculate the speed of rotation of the disc.

• A. 10 rev/s
• B. 20 rev/s
• C. 24 rev/s
• D. 8 rev/s.