Give three observations in support of de Broglie's assumption that moving particles behave like waves

(a) Explain the terms:- uniform acceleration and average speed.

(b) A body at rest is given an initial uniform acceleration of 8.0ms\(^{-2}\) for 30s after which the acceleration is reduced to 5.0ms\(^{-2}\) for the next 20s. The body maintains the speed attained for 60s after which it is brought to rest in 20s. Draw the velocity-time graph of the motion using the information given above.

(c) Using the graph, calculate the: (i) maximum speed attained during the motion; (ii) average retardation as the body is being brought to rest; (iii) total distance travelled during the first 50s; (iv) average speed during the same interval as in (ii).

Which of the following electromagnetic waves is most energetic?

• A. Radio waves
• B. X-ray
• C. Gamma rays
• D. Ultra-violet rays

(a) Distinguish between stress and strain as used in elasticity.

(b) When a force of 40 N is applied to the free end of an elastic cord, an extension of 5cm is produced in the cord. Calculate the work done on the cord.

In a domestic circuit, electrical appliances and lamps are arranged in parallel across the mains so as to enable the

• A. same current to flow through the electrical appliances and the lamps
• B. maximum energy to be consumed at least cost
• C. same fuse to be used for the electrical appliances and the lamps
• D. voltage across the appliances not to be affected when the lamps are switched on and off

(a) Explain how a gas can be made to conduct electricity.

(b) Name the electric charge carriers in gases.

A vapour whose molecules are in dynamic equilibrium with those of its own liquid is said to be

• A. unsaturated
• B. gaseous
• C. saturated
• D. diffused

Which of the following are emitted from a radioactive substance without altering either the nucleon number or the proton number of the substance?

• A. Protons
• B. Neutrons
• C. Gamma rays
• D. Beta particles

A resultant force of magnitude 15N acts on a body of mass 250g. Calculate the magnitude of the acceleration

• A. 0.06 ms^-2
• B. 3.75ms^-2
• C. 16.67ms^-2
• D. 60.00ms^-2

Which of the following is the dimension of pressure?

• A. ML^-1T^-2
• B. MLT^-2
• C. ML²T^-3
• D. ML^-3