Calculate the inductive reactance of the circuit shown below.

• A. 50.00
• B. 5.00
• C. 0.50
• D. 0.05

Which of the following is used for controlling the amount of light entering the eye?

• A. Cornea
• B. Pupil
• C. Iris
• D. Optic nerve

The periodic rise and fall in the intensity of sound produced whn two notes of nearly equal frequencies are sounded together is called? The periodic rise and fall in the intensity of sound produced whn two notes of nearly equal frequencies are sounded together is called?

• A. doppler effect
• B. beat
• C. interference
• D. resonance

A radioactive isotope has a decay constant of 10^-6s^-1. Calculate its half - life?

• A. 5.93 x 10⁶s
• B. 6.93 x 10⁵s
• C. 6.93 x 10⁹s
• D. 5.93 x 10⁷s

The molecular structure of a liquid is such that

• A. the molecules have unlimited freedom of movement
• B. molecular movement is restricted to vibration only
• C. intermolecular collisions take place
• D. all molecules moves move with the same speed

The lowest note emitted by a stretched string has a frequency of 40Hz. How many overtones are there between 40Hz and 180Hz?

• A. 4
• B. 3
• C. 2
• D. 1

The amount of energy required to change a kilogram of ice in water without a change in temperature is

• A. heat capacity of ice
• B. specific heat capacity
• C. specific latent heat of vaporisation of ice
• D. specific latent heat of fusion of ice

When a ball rolls on a smooth level ground, the motion of its center is

• A. translational
• B. oscillatory
• C. random
• D. rotational

(a)(i) State Einstein's equation of photoelectric effect

(ii) What conservation principle does the equation represent?

(b) List three applications of photocells

(c) A photo emissive surface has a threshold frequency of 4.02 x 10\(^{14}\)Hz. If the surface is illuminated by light of frequency 5.0 x 10\(^{15}\)Hz, calculate the:

(i) threshold wavelength;

(ii) work function;

(iii) kinetic energy of the emitted photoelectrons. [ c = 3.0 x 10\(^{8}\) ms\(^{-1}\), h = 6.63 x 10\(^{-34}\) Js]

A body is pulled over a distance of 500m by a force of 20N. If the power developed is o.4 kW, calculate the time interval during which the force is applied

• A. 0.2s
• B. 2.5s
• C. 25.0s
• D. 250.0s