(a) What is doping in a semi conductor?

(b) Draw the symbol for OR gate.  

The circuit above consists of an a. c. voltage input, a diode, a resistor and a voltmeter.

(a) Identify the circuit.

(b) Draw the waveform for the output voltage.

(a) Write the de Broglie equation.

(b) Explain the significance of the equation.

(a) (i) Define uniform acceleration.

(ii) Write an equation that relates linear velocity, angular velocity and radius
of path in circular motion.

(b) Two forces 30 N and 40 N act at right angles to each other. Determine by scale drawing, the magnitude and direction of the resultant force,.using a scale of 1 cm to 5 N.

(c) Explain why ships are usually refilled with sand and water after they have been emptied of their cargo.

(d) A crate of drinks of mass 20 kg is placed on a plane inclined at 30° to the horizontal. If the crate slides down with a constant speed, calculate the:

(i) co-efficient of kinetic friction;

(ii) magnitude of the frictional force acting on the crate. [ g = 10 ms\(^{-2}\)]

(a) Define specific latent heat of vaporization.

(b) (i) What are renewable energy sources?

(ii) List four renewable energy sources.

(c) Explain why tomatoes keep longer when kept in a moist jute bag in a clay pot.

(d) A box has a volume of 0.28 m\(^3\) and is 70% filled with iron fillings at 25°C. Calculate the:

(i) total mass of the iron fillings;

(ii) energy required to melt 10% of the iron fillings. [Density of iron = 8.00 x 10\(^3\) kgm\(^{-3}\); specific latent heat of fusion of iron = 1.38 x 10\(^5\) Jkg\(^{-1}\), specific heat capacity of iron = 460 Jkg\(^{-1}\) k\(^{-1}\), melting point of iron = 1500°C] 10.