A ray of light is incident normally on one face of a right angled isosceles prism. It then grazes the hypotenuse. The refractive index of the material of the prism is
1.33
1.414
1.5
1.732
B.
1.414
where C is the critical angle.
Two thin equiconvex lenses each of focal length 0.2 m are placed coaxially with their optic centres 0.5 m apart. Then the focal length of the combination is
− 0.4 m
0.4 m
− 0.1 m
0.1 m
A prism of a certain angle deviates the red and blue rays by 8° and 12° respectively. Another prism of the same angle deviates the red and blue rays by 10° and 14° respectively. The prisms are small angled and made of different materials. The dispersive powers of the materials of the prisms are in the ratio
5 : 6
9 : 11
6 : 5
11 : 9
When the angle of incidence is 60° on the surface of a glass slab, it is found that the reflected ray is completely polarised. The velocity of light in glass is
2 × 108 ms-1
3 × 108 ms-1
A 20 cm length of a certain solution causes right handed rotation of 38°. A 30 cm length of another solution causes left handed rotation of 24°. The optical rotation caused by 30 cm length of a mixture of the above solutions in the volume ratio 1 : 2 is
left handed rotation of 14°
right handed rotation of 14°
left handed rotation of 3°
right handed rotation of 3°
Minority carriers in a p-type semiconductor are
free electrons
holes
neither holes nor free electrons
both holes and free electrons
In a reverse biased diode when the applied voltage changes by 1 V, the current is found to change by 0.5 µA. The reverse bias resistance of the diode is
2 × 105 Ω
2 × 106 Ω
200 Ω
2 Ω