Page 214 - Physics_Form_2

Physics for Secondary Schools

(b) Figure 5.44 shows a ray of light Given that the three media
travelling from air to water. are air, glass, and water (not
in order), which medium is
represented by letters P, Q, and
R, respectively?
(i) Air, glass, water.
FOR ONLINE READING ONLY
(ii) Air, water, glass.
Air 40° (iii) Glass, air, water.

Water
(iv) Glass, water, air.

(d) The radius of curvature of the
curved surface of a thin plano-
Figure 5.44 convex lens is 10 cm and the

Given that the refractive index refractive index is 1.5. If the
of water is 4/3, what is the angle plane surface is silvered, then
of refraction of the ray of light? the focal length will be:

(i) sin  1   4 sin (40 )   (i) 5 cm (ii) 10 cm
(iii) 15 cm (iv)
20 cm
 3 
(ii) sin  1   3 sin (50 )   (e) A ray of light travelling in
a transparent medium of
 4  refractive index η, falls on a
(iii) sin  1   4 sin (50 )   surface separating the medium
 3  from the air at an angle of

(iv) sin  1   3 sin (40 )   incidence of 45º. The ray can
 4  undergo total internal reflection
for the following:
(c) Figure 5.45 shows a ray of
light travelling through three (i) η =1.25 (ii) η =1.33
different media. (iv) η =1.5
(iii) η =1.4
(f) An air bubble in a glass slab

P of refractive index 1.5 (near
normal incidence) is 5 cm deep

Q when viewed from one surface
and 3 cm deep from the opposite
face. The thickness of the slab
R
is,
(i) 8 cm (ii) 10 cm

Figure 5.45 (iii) 12 cm (iv) 16 cm

208
Student’s Book Form Two

Physics Form 2 Final.indd 208 25/10/2025 10:28