The expected answers are;

(a)(i) A wave motion is a process of transferring a disturbance (in form of kinetic energy) from one point to another in a medium without any transfer of the particles of the medium.

(ii)Any two correct differences between radio and sound waves e.g.
-Radio wave is electromagnetic while sound wave is mechanical.
-Radio wave is transverse while sound wave is longitudinal;
-Radio wave does not require a material medium for its propagation while sound wave does;
- Radio wave has a velocity equal to that of light while the velocity of sound wave is less than that of light.

Description

-Fill the burette with water.
-Set the prongs of the turning fork into vibration and bring the fork near the open end of the burette
-Gradually increase the length of the air column in the tube by opening the tap to run out some water, until a loud sound is heard
-Measure and record the length l of the air column;
-Further run out the water while the vibrating tuning fork is still held over the open end of the burette until a second loud sound is heard;
-Record the length l2 of the air column;
-Repeat the experiment to obtain I1 and l2 again. Obtain mean values of l1
The frequency of the tuning fork is given by the equation.
          f = v/2(l1 – l2)
Note: For theory accept, v/41 for candidates using only one resonance length, but such candidates can score a max of 3 marks for description.
(ii) Any two of the following precautions:
two lengths of air column are obtained to take care of end correction' tap turning fork on a pad not on a hard surface
hold turning fork carefully over the burette to avoid contact repeat the experiment (to obtain mean value)
( c ) Frequency fo of the fundamental note is given by the equation.
          f o = v/4l

                             =   340
                                   4 x 100 x 10-2

                               = 85 Hz

This question on waves attracted very few candidates. The performance was also poor.

In part (a), the candidates had a lot of difficulty defining wave motion. Most of them were able to distinguish between radio and sound waves using the properties and characteristics of the waves. .'

The description of the experiment, with the aid of a diagram, to determine the frequency of a note posed a lot of difficulty to the candidates. While some of the candidates could not present well labelled diagrams, others could not present a logical description of the experiment

The numerical problem in part (c) was fairly well handled by most of the candidates. They were able to recall the correct formula as f = v/4l substitute correctly and carry out the arithmetic.