1. (a) Define boiling point of a liquid.

(b) Describe how water in a round bottom flask could be made to boil without heating it. [diagram not necessary]

(c) State three applications of expansion of metals.

(d) A room with floor measurements 7m x 10 m contains air of mass 250 kg at a temperature of 34°C. The air is cooled until the temperature falls to 24°C. Calculate the: (i) height of the room;

(ii) quantity of energy extracted to cool the room;

(iii) which is higher: the calculated value or the actual energy needed to cool the room? Give a reason for your answer. [ Specific heat capacity of air = 1010 Jkg−1K−1; density of air = 1.25 kg m\(^{-3}]

2.(a) Explain briefly the purpose of earthing electrical appliance.

(b) Why does the light frorr bulb connected to a simple cell dim and eventually goes off after a while?

(c) A coil of incidence 0.007 H, a resistor of resistance 8 Ω and a capacitor capacitance 0.001 F are connected in series an a.c. source of frequency 500/πHz. If the r.m.s voltages across the coil, the resistor and capacitor are 30v, 20v and 70v respectively;

(i) draw a vector diagram to illustrate the voltage across the components in the circuit.

(ii) Calculate the: (α) r.m.s voltage of the source

(β) r.m.s current in the circuit;

(γ) power dissipated in the circuit.

iii) write down the sinusoidal equation for the r.m.s voltage, V, in terms of the time, t.

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3.Name one use of ‘LASER’ in each of the following areas:

(a) communication;

(b) medicine;

(c) security

4. The accelerating potential in a cathode ray oscilloscope is 2.5 kV. Calculate the maximum speed of the accelerated electrons. [ e = 1.6 x 10^−19 C; Me = 9.1 x 10^−31 kg]

5. Write down the name of:

(a) two particles used in explaining the wave nature of matter;

(b) one device whose invention is based on the wave nature of matter.

6.(a) what is Brownian motion?

(b) State the two inferences that can be drawn from Brownian motion experiment.

7. A projectile is released with a speed u at an angle 0 to the horizontal. With the aid of a diagram, show that the time of flight is equal to 2uSinθ/g, where g is the acceleration of free fall.

8. The horizontal component of the initial speed of a particle projected at 30° to the horizontal is 50 ms−1. If the acceleration cf free fall due to gravity is 10ms−2, determine its: (a) initial speed; (b) speed at maximum height reached.

9. In an electrolysis experiment, the ammeter records a steady current of 1 A. The mass of copper deposited in 30 minutes is 0.66 g. Calculate the error in the ammeter reading. [Electrochemical equivalent of copper = 0.00033 g C−1]

10. (a) What is a polarizer?

(b) With the aid of a diagram, explain how a polarizer can be used to polarize a beam of unpolarized light.