A spiral spring of natural length 30.0cm and force constant of 20Nm^-1 is compressed to 20.0cm. Calculate the energy stored in the spring

• A. 0.1J
• B. 1.0J
• C. 10.0J
• D. 100.0J

A girl standing some distance from the cliff claps her hands and hears the echo 0.8s later. calculate her distance from the cliff. [speed of sound in air = 320 ms^-1]

• A. 23m
• B. 128m
• C. 288m
• D. 298m

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

Light of wavelength 589 nm in vacuum passes through a piece of fused quartz of index of refraction n = 1.458. What is the frequency of the light in fused quartz?

[Speed of light c = \(3.00×10^8 ms^-1\)

• A. \(5.09
• B. \(5.09
• C. \(1.77
• D. \(1.77

in a pure semiconductor, the number of electrons in the conduction band is

• A. less than the number of holes in the valence band
• B. equal to the number of holes in the valence band
• C. greater than the number of holes in the valence band
• D. twice the number of holes in the valence band

The diagram below represents the graph of electron energy against the frequency of the radiation incident on a metal surface. Interpret the: (a) slope of the graph; (b) intercept, OC; (c) intercept, OK.

Study the diagram below and answer question The farm tool associated with the diagram below is

• A. Knife
• B. Secateurs
• C. Shears
• D. Cutlass

An astronomical telescope is said to be in normal adjustment when the?

• A. eye is accommodated
• B. focal length of an object lens is longer than that of eye piece
• C. final image is at the near point of eye
• D. final image is at infinity

The fundamental frequency of vibration of a sonometer wire may be halved by

• A. doubling the length of the wire
• B. doubling the mass of the wire
• C. reducing the tension by half
• D. reducing the absolute temperature by half

Which of the following wave is electromagnetic?

• A. x-rays
• B. sound waves
• C. water waves
• D. tidal waves