A solenoid is constructed by winding an insulated copper on a long test tube. A constant direct current is passed through the solenoid. Which of the following actions will not increase the strength of the magnetic field of the solenoid? Inserting a

• A. steel rod in the test tube
• B. Nickel rod in the test tube
• C. Brass rod in the test tube
• D. Soft iron rod in the test tube

The main difference between echo and reverberation is that

• A. reverberation is reflected sound while echo is refracted sound
• B. the time interval between incident sound and reflecte sound is shorter for reverberation
• C. the amplitude of an echo is greater
• D. reverberation is from acoustic speakers while echo comes from clifts

(a) State two factors that affect the rate of evaporation of a liquid.

(b) Explain the term latent heal.

(c) Explain each of the following phenomena:

(i) On a dry day, water in a clay pot is cooler than water in a rubber container:

(ii) Cooking of food is faster in a pressure cooker than in an ordinary pot.

(d) A 40 V electric heater is used to supply a current of 12 A for 1400 seconds to a body mass of 1.5 kg at its melting point. The body melts and its temperature rises by 60°C in an extra 1.2 minutes, Calculate the:

(i) Latent heat of fusion of the body

(ii) Specific heat capacity of the body.

(e) State two differences between evaporation and boiling.

(a) What is doping?

(b) Explain how doping improves the conductivity of a semiconductor

Which of the following are true of plane-polarised right? i. Plane polarisation of light is the formation of hydrogen bubbles on the particle of light. ii. Plane components. iii. A plane polarised light vibrates in one plane. iv. Polarisation of light is characteristic of transverse vibration

• A. i and ii only
• B. i and iv only
• C. ii and iii only
• D. i and ii only

The thermometric substance of an absolute thermometer is

• A. alcohol
• B. mercury
• C. helium
• D. platinum

A satellite is in a parking orbit if its period is

• A. less than the period of the earth
• B. more than the period of the earth
• C. equal to the period of the earth
• D. the square of the period of the earth

Which of the following types of waves needs a medium for propagation?

• A) sound waves
• B) light waves
• C) radio waves
• D) x - rays

(a) Define uniform acceleration.

(b) Forces act on a car in motion. List the

(i) horizontal forces and their directions;

(ii) vertical forces and their directions

(c) A car starts from rest and accelerate uniformly for 20s to attain a speed of 25 ms\(^{-1}\). It maintains this speed for 30s before decelerating uniformly to rest. The total time for the journey is 60s.

(i) Sketch a velocity-tune graph for the motion.

(ii) Use the graph to determine the (\(\alpha\)) total distance travelled by the car (\(\beta\)) deceleration of the car.

The figure here illustrates force-extension graph for a stretched spiral spring. Determine the work done on the spring.

A constantan wire has a cross sectional area of 4 x 10^-8m² and a resistivity of 1.1 x 10^-6\(\Omega\)m. If a resistor of resistance 11\(\Omega\) is to be made from this wire, calculate the length of the wire required

• A. 0.4m
• B. 0.8m
• C. 2.5m
• D. 5.0m