Physics Past Questions and Answers

(a) Explain wave-particle duality of light.<br/>(b) Illustrate your answer in (a) with observable phenomena.

(a) State the principle of conservation of linear momentum.<br/>(b) Explain the mode of action of a propelled rocket.<br/>(c) During a training session, two footballers pass a ball repeatedly between themselves. Give two reasons why the to and fro motion of the ball is not simple harmonic.<br/>(d) A ball is dropped from a height, at the same time as another ball is projected horizontally from the same height.<br/>(i) Would the balls hit the ground at the same time?<br/>(ii) Explain your answer in (i).<br/>(e) A ball of mass 0.10 kg is projected horizontally onto a vertical wall with a speed of 17 ms\(^{-1}\). The ball makes contact with the wall for 0.15 s and rebounds horizontally with a speed of 13 ms\(^{-1}\).<br/>Calculate the:<br/>(i) change in momentum of the ball;<br/>(ii) average force exerted on the ball during its collision with the wall.

(a) (i) What is a machine?<br/>(ii) State two uses of gears.<br/>(iii) Define the velocity ratio for a pair of gear wheels.<br/>(iv) How can the mechanical advantage of a gear system be increased?<br/><br/>The diagram above illustrates the gears system of a bicycle.<br/>(i) Determine its velocity ratio.<br/>(ii) If the bicycle has an efficiency of 90%, calculate the effort required to overcome a load of 70N.<br/>(iii) Why is the calculated effort less than the actual effort required?

(a) Explain the term critical angle.<br/>(b) List two factors which determine the deviation of a ray of light by a triangular glass prism.<br/>(c) The angle of refraction (r) of a ray of white light from air through a triangular glass prism of refractive index 1.5 is 29.0°. Calculate the angle through which the ray is least deviated.<br/>(d) Study the ray diagram below and use it to answer the questions that follow.<br/> <br/><br/> <br/>Calculate the:<br/>(i) values of angles P,Q and R;<br/>(ii) refractive index n of the glass prism;<br/>(iii) value of e;<br/>(iv) total deviation D.

(a) Define magnetic line of force.<br/>(b) A wire of length 10 cm carrying a current of 4.0 A is placed between the poles of a powerful electromagnet of magnetic flux density 2.0 T. Calculate the:<br/>(i) force on the wire when it is parallel to the field;<br/>(ii) maximum force on the wire;<br/>(iii) force on the wire when it makes an angle of 60° with the field.<br/>(c) Describe how keepers can be used to preserve the magnetic strength of permanent bar magnets.<br/>(d) A sailor observes that his mariners' compass reads N 10° W at a place where the angle of declination is N15° W. Calculate the true bearing of the place.