are moving.
(c) Sound waves can travel through vacuum.
(d)The specific heat capacity of water is 4619 J Kg-1 K-1.
2.Fill in the balnks with a suitable word or words. (4 marks)
(a)When an object is at the centre of curvatureof a concave mirror the magnification is
________ .
(b)The distance between the pole and the focus of a concave or convex mirror is called
the ________ of a concave or convex mirror.
(c) The velocity of light in air is _____ ms-1.
(d) The electrons closer to the nucleus are called _____ electrons.
- (a) State the laws of reflection of light. Find the wavelength of a wave with frequency 1000 Hz and velocity
344 ms-1. (3 marks )
(b) A concave mirror can produce an image which is twice the size of the object. Draw a ray diagram to show
this. (3 marks )
- (a) Define specific heat capacity. A calorimeter at 15 ℃ contains 0. 1 kg of carbon. The calorimeter is made
of aluminum and its mass is 0.02 kg. When 892 J of heat is added to the calorimeter and carbon, the
temperature increases to 28 ℃ . Find the specific heat capacity of carbon. Assume that the specific heat
capacity for aluminum at said temperature range is 900 J kg-1 K-1. (3 marks )
(b) A radar antenna of a wave with frequency 1000 Hz and wavelength 0.5 m. (3 marks )
- (a)The glancing angle of a ray incident on a plane mirror is 60° . Find the angle between the incident ray and
the new reflected ray when the plane mirror is rotated(a) through 15° in the clockwise direction,(b)through
30° in the anticlockwise direction. (3 marks )
(b) A 60 kg woman is on a diet that provides her with 1.046 J daily . If this amount of heat is added to 60 kg
of water at 37° will be the final temperature of the water? (3 marks )
SECTION (B)
(Answer ALL questions)
- (a) 0.5 kg of orange squash at 30℃ is placed in a refrigerator which can remove heat at an average rate of
25Js-1. How long will it take to cool the orange squash to 5℃?The specific heat capacity of orange squash
is 4200 J kg-1℃-1. (4 marks )
(b) An object is 200cm in front of a concave mirror of focal length 15cm.How far must the screen be placed
from the centre of curvature of the concave mirror to receive the image of the object? If the object is 2cm
tall, find the size of the image. (4 marks )
