The terminal velocity of a ball-bearing falling through a viscous fluid reached when the

• A) upthrust is equal to the weight of the ball
• B) ball accelerate uniformly
• C) upthrustis equal to the velocity of the ball
• D) velocity is uniform

After three half lifes, the fraction of a radioactive material that has decayed is

• A. \(\frac{1}{8}\)
• B. \(\frac{1}{3}\)
• C. \(\frac{2}{3}\)
• D. \(\frac{7}{8}\)

A beam of light is incident from air to water at an angle of 30^oC. Find the angle of refraction if the refractive index of water is \(\frac{4}{3}\)

• A. 15^oC
• B. 18^oC
• C. 22^oC
• D. 24^oC

The following statements about a loudspeaker are correct except?

• A. its contains a permanent magnet.
• B. sound signal converted to varying current signal enters the speech coil.
• C. the current in the speech coil creates a magnetic force on the coil.
• D. the magnetic force on the speech coil is uni-directional.

The angle of deviation of light of various colours passing through a glass prism decreases in the order of

• A. blue orange and red
• B. red, blue and orange
• C. blue, red and orange
• D. red, orange and blue

A wire gradually stretched by loading it until it snaps.

(a) Sketch a load-extension graph for the wire

(b) Indicate on the graph the

(i) elastic limit (E);

(ii) yield point (Y);

(iii) breaking point (B).

A galvanometer with a full-scale deflection of 20 mA is Converted to read 8 K by connecting a 395 \(\Omega\) resistor in series with it. Determine the internal resistance of the galvanometer

• A. 2.5\(\Omega\)
• B. 5.0\(\Omega\)
• C. 8.0\(\Omega\)
• D. 10.0\(\Omega\)

A mass of mass m, experiences a viscous drag, F and an upthrust, U as he descends towards the ground at a steady velocity, Using a parachute. If the acceleration of free fall is g, which of the following expressions is correct?

• A. FU = mg
• B. U + F - mg = 0
• C. U - F = mg
• D. F - U - mg = 0

(a) Define the boiling point of a liquid.

(b) With the aid of a sketch diagram, describe an experiment to determine the boiling point of a small quantity of a Iiquid

(c) A piece of copper of mass 300 g at a temperature of 950°C is quickly transferred into a vessel of negligible thermal capacity containing 250 g of water at 25°C. If the final steady temperature of the mixture is 100°C, calculate the mass of water that will boil away. Especific heat capacity of copper = 4.0 x 10\(^2\) J kg\(^{-1}\)K\(^{-1}\) specific heat capacity of water = 4.2 x 10\(^{3}\) J kg\(^{-1}\)K\(^{-1}\) specific latent heat of vaporization of steam = 2.26 x 10\(^6\)J kg\(^{-1}\)

A body weighing 10 N in air is partially immersed in water. It displaces water of mass 0.3 kg. What is the upthrust on the body? (g = 10 ms^-2)

• A. 13.0 N
• B. 7.0 N
• C. 3.3N
• D. 3.0N