ai. State the reason why simple harmonic motion is periodic.

ii. State two factors that affect the period of oscillation of a simple pendulum.

iii. Sketch a graph of the total mechanical energy, E, against displacement, y, for the motion of a simple pendulum from one extreme position to the other.

b. The diagram below illustrates an oscillatory pendulum. Calculate the work done in raising the pendulum to point B, if the mass of the bob is 50 g.

[g = \(10 ms^2\)]

c. A spiral spring of spring constant, k, and natural length, l, has a scale pan of mass 0.04 kg hanging on its lower end while the upper end is firmly fixed to a support. When an object of mass 0.20 kg is placed on the scale pan, the length of the spring becomes 0.055 m and when the object is replaced with another object of mass 0.28 kg, the length of the spring becomes 0.065 m. Calculate the values of k and l.

[g = \(10 ms^2\)]

If the threshold frequency for tungsten is 1.3 x 10¹⁵Hz, what is its work function?

[H = 6.6 x 10^-34 Js]

• A) 8.58 x 10-19 J
• B) 8.50 x 10-15 J
• C) 8.58 x 10-17 J
• D) 8.85 x 10-18

The images formed by diverging lenses are always

• A. diminished, virtual and inverted
• B. diminished, virtual and errect
• C. diminished inverted and real
• D. magnified, virtual and errect

The working principle of a pressure cooker is based on the

• A. increase in the volume of steam inside it
• B. complete trapping of heat inside it
• C. increase in the pressure of the pot
• D. decrease in the pressure of the pot

A metal rod 800mm long is heated from 10^oC to 95^oC. If it expands by 1.36mm, the linear expansivity of the metal is

• A. 2.0 x 10²K^-1
• B. 2.0 x 10²K^-1
• C. 5.0 x 10^-3K^-1
• D. 2.0 x 10^-5K^-1

In free fall, a body of mass 1kg drops from a height of 125m from rest in 5s. How long will it take another body of mass 2kg to fall from rest from the same height? [g = 10ms^-1·]

• A. 5s
• B. 10s
• C. 12s
• D. 15s

the shortest length of the air column in a resonance tube at resonance is 0.12m and the next resonance length is 0.37m. calculate the frequency of vibration given that the speed of sound in air is 340m^-1

• A. 1360Hz
• B. 694Hz
• C. 680Hz
• D. 34Hz

A stone projected horizontally from the top of a tower with a speed of 4 ms\(^{-1}\) lands on the level ground at a horizontal distance of 25 m from the foot of the tower. Calculate the height of the tower. = 10 ms\(^{-2}\)]

Which of the following factors does not affect the the electric resistance of a wire?

• A. length
• B. mass
• C. temperature
• D. cross sectional area

(a) What is meant by 'a beam of polarised light?

(b) With the aid of well labelled diagrams, illustrate the action in of a polaroid spectacle on a beam of sunlight.