The process whereby the molecules of different substances move randomly is called?

• A. capillarity
• B. surface tension
• C. osmosis
• D. diffusion

The half-life of a radioactive substance is 15 hours. If at some instance, the sample has a mass of 512 g, calculate the time it will take \(\frac{7}{8}\) of the sample to decay

• A. 15 hours
• B. 30 hours
• C. 45 hours
• D. 60 hours

Sixty complete waves pass a particular point in 4s. lf the distance between three successive troughs of the waves is 15m, calculate the speed of the waves,

• A. 300.0ms^-1
• B. 225.0ms^-1
• C. 112.5ms^-1
• D. 75.0ms^-1

At a fixed point below a liquid surface, the pressure downwards is P1 and pressure upwards is P2. It can be deduced that

• A. P1 > P2
• B. P1 ≥ P2
• C. P1< P2
• D. P1 = P2

(a) Define surface tension

(b) State two methods by which the surface tension of a liquid can be reduced

A motor boy of a driver saw what seems to appear to be a pool of water a head of him, while his driver drives a new truck on a sunny day. Which of the following explains his observation?

• A. He saw a flying objects
• B. He must be thinking of water and food
• C. He was seeing the shadow of the car
• D. The sun ray from the sky were passing from a hot air (layer) to cold layer

A battery of emf 24V is connected to three resistor P, Q and R as illustrated in the diagram. Determine the voltage across the resistor Q

• A. 5v
• B. 10v
• C. 14v
• D. 24v

Calculate the current, I in the diagram shown below. (Neglect the internal resistance of the cell)

• A. 4.0A
• B. 2.0A
• C. 1.0A
• D. O.5A

The mouth piece of a telephone handset converts

• A. electrical energy to sound energy
• B. sound energy to electrical energy
• C. sound energy to radiowave
• D. radiowave to sound energy

When the temperature of a liquid increases, its surface tension

• A. decreases
• B. increases
• C. remains constant
• D. increases then decreases