1.(a) state the
(i) Law of conservation of moment
(ii) Factors on which linear momentum depends
(b)Explain what happens when a balloon is filled with air and then released in space without trying its open end.
(c ) Explain what happens to a passenger in a bus ,when the driver breaks suddenly.
(d)Define the following terms
(i) Displacement
(ii) Force
(e)With the aid of a labeled diagram, describe an experiment to measure a uniform velocity or a body using a ticker timer.
2. (a) Define a moment of force.
(b) describe an experiment to determine the mass of a uniform meter rule using the principle of moments.
(c ) Figure 1 shows a uniform pole AB of length 2m and weight 50N supported at the ends A and B. A load of weight 500 N is suspended at a point 50cm from A.
Calculate the reaction forces R1 and R2 at the supports.
(d)(i) Explain what is meant by unstable equilibrium.
(ii) State two ways of increasing the stability of a body
3(a) Define the following terms
(i) Strain
(ii) Tensile force.
(b)with the aid of a diagram, describe an experiment to verify hooke's law using a spring.
(c ) (i) A material of mass 2kg requires 4.4x103 J for its temperature to change from 600c to 800c . calculate its specific heat capacity.
(ii)If the material in (d) (i) is placed in a vacuum, state why it cools.
4(a) Describe with the aid of a labeled diagram the operation of a transformer.
(b)A 240 v step-down mains transformer is designed to light ten 12v, 20w ray box lamps and draws a current of 1A in the primary coil .
Calculate the:
(i) Power supplied to the primary coil
(ii) Power developed in the secondary coil
(iii) Efficiency of the transformer
(c) With the aid of suitable diagrams, distinguish between an alternating current and a direct current.
(d) Explain how a fuse as a safety device achieves its function in house wiring.
5. (a) Distinguish between thermionic and photoelectric emission.
(b) Ultra violet radiations are incident on a clean zinc plate resting on the cap of a charged gold leaf electroscope as shown in figure 2. Explain what is observed if:
(i) The gold leaf electroscope is positively charged
(ii) Radio waves is used instead of ultra violet radiations
(c ) (i) with the aid of a labeled diagram, describe how X-rays are produced in an X-ray tube.
(ii)Explain why soft x-rays are used instead of hard X-rays to take photographs of internal parts of a patient in hospitals.
6. (a) Define the terms
(i) amplitude
(ii) wavelength
(b) Draw diagrams to show how circular water ripples are reflected from
(i) concave reflector
(ii) convex reflector
(c ) (i) distinguish between longitudinal waves and transverse waves.
(ii)Give one example of each of the waves in (c ) (i).
(d)State four properties of electromagnetic waves.
(e) the distance between two successive antinodes on a standing wave is 3.0 cm. if the distance between the source of wave and reflector is 24.0cm, find the
(i) number of loops
(ii) wavelength of the wave
7. (a) Define the following terms as applied to curved mirrors
(i) center of curvature
(ii) principal axis
(b) explain with the aid of a ray diagrams, why a parabolic mirror is preferred to a concave mirror as a car head lamp.
(c ) An object of height 5 cm is placed 15 cm in front of a concave mirror of radius of curvature 20cm. by scale drawing, find the
(i) Image distance from the mirror
(ii) Height of the image
(d)(i) with the aid of ray diagrams, explain how regular and diffuse reflections are produced.
(ii) state the characteristics of images formed in plane mirrors
8. (a) what is meant by?
(i) radiocavity
(ii) half life
(b) what happens to the activity of a radioactive material when its
(i) mass is increased
(ii) temperature is increased
(c ) A material is wrapped in a photographic film and kept in a dark room when the photographic film is removed, it is found to be darkened.
(i) Identify the material
(ii) Explain the observation
(d). a radioactive substance of mass 60 g takes 400 years for its mass to be reduced to 15g. find its half life.
(e) state:
(i) two industrial and two medical uses of radioactivity
(ii) two health hazards of radioactivity