A given wire of resistance 10 Ω has a length of 5 m and a cross-sectional area of 4.0 × 10\(^{-3}\) m\(^2\). Calculate the conductivity of the wire.

Calculate the inductive reactance of the circuit shown above

1a. Explain what is meant by the acceleration of free fall due to gravity, g.

b. State two reasons why g varies on the surface of the Earth.

c. A stone is projected upwards at an angle of 30° to the horizontal from the top of a tower of height 100 m and it hits the ground at a point Q. If the initial velocity of projection is 100 ms\(^{-1}\), calculate the:

i. maximum height of the stone above the ground (neglect air resistance and take g as 10 ms\(^{-2}\))

ii. time it takes to reach this height

iii. time of flight.

iv. horizontal distance from the foot of the tower to the point Q (neglect air resistance and take g as 10 ms\(^{-2}\))

2a. State Faraday's law of electromagnetic induction.

b. Draw a labelled diagram of an induction coil and explain how it works.

c. How is the effect of eddy currents minimized in the coil?

d. State two reasons why a capacitor should be included in the primary circuit of the coil.

e. State three uses of an induction coil.

3a. What is surface tension? Explain the phenomenon in terms of intermolecular forces.

b. Describe a simple experiment to demonstrate the surface tension of a liquid.

c. State three examples to illustrate the effects of surface tension.

d. Why does water wet a clean glass surface, whereas mercury does not?

e. State two methods by which the surface tension of a liquid may be reduced.