Calculate the energy required to vapourise 50g of water initially at 80^oC.[specific heat capacity of water = 2260Jg^-1K^-1][specific latent heat of vaporisation of water = 2260Jg^-1]

• A. 113,000J
• B. 117,200J
• C. 234,400J
• D. 420,000J

A pulse of a sound is transmitted from a ship and the reflection from the sea bed is recorded after 0.2s. Calculate the depth of the sea. [Take speed of sound in sea water = 1560ms^-1]

• A. 312.0m
• B. 156.0m
• C. 78.0m
• D. 31.2m

What type of motion does the skin of a 'talking' drum perform when it is struck with a drum stick?

• A. Random
• B. Rational
• C. Translational
• D. vibratory

The refractive index of a medium relative to air is 1.8. Calculate to the nearest degree, the critical angle for the medium

• A. 68°
• B. 56°
• C. 34°
• D. 18°

A stone thrown horizontally from the top of a vertical ice is completely melted. Determine the total mass of wall with a velocity of 15ms\(^{-1}\), hits the horizontal ground water in the container at a point 45m from the base of the wall. Calculate the specific latent heat of steam = 2.3 x 10\(^3\) Jg\(^{-1}\) height of the wall. [g = 10ms\(^{-2}\)]

A slinky spring fixed at one end is placed horizontally on a table. The free end is displaced parallel to the table and then released. The resultimg wavelength is

• A. transverse
• B. longitudinal
• C. stationary
• D. electromagnetic

(a) Explain diffusion

(b) State one factor that can affect the rate of diffusion.

In the wave equation y = E_o, sin(299t - \(\pi\)), E_o represents the

• A. amplitude
• B. frequency
• C. period
• D. wavelength

A block and tackle system has 6 pulleys. If the efficiency of the machine is 60%, determine its mechanical advantages

• A. 12.0
• B. 10.0
• C. 3.6
• D. 1.8

Local actions is normally prevented in a simple electric cell by

• A. introducing an oxidizing agent in the acid
• B. not drawing current continously for long period
• C. amalgamating the surface of the zinc plate
• D. using a porous pot to isolate the zinc plate from the acid