A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power
+ 0.5 D
- 0.5 D
+ 0.2 D
- 0.2 D
A student sitting on the last bench can read the letters written on the blackboard but is not able to read the letters written in his text book. Which of the following statements is correct?
The near point of his eyes has receded away
The near point of his eyes has come closer to him
The far point of his eyes has come closer to him
The far point of his eyes has receded away
A prism ABC (with BC as base) is placed in different orientations. A narrow beam of white light is incident on the prism as shown in Figure 11.1. In which of the following cases, after dispersion, the third colour from the top corresponds to the colour of the sky?
(i)
(ii)
(iii)
(iv)
At noon the sun appears white as
light is least scattered
all the colours of the white light are scattered away
blue colour is scattered the most
red colour is scattered the most
Which of the following phenomena of light are involved in the formation of a rainbow?
Reflection, refraction and dispersion
Refraction, dispersion and total internal reflection
Refraction, dispersion and internal reflection
Dispersion, scattering and total internal reflection
Twinkling of stars is due to atmospheric
dispersion of light by water droplets
refraction of light by different layers of varying refractive indices
scattering of light by dust particles
internal reflection of light by clouds
The clear sky appears blue because
blue light gets absorbed in the atmosphere
ultraviolet radiations are absorbed in the atmosphere
violet and blue lights get scattered more than lights of all other colours by the atmosphere
light of all other colours is scattered more than the violet and blue colour lights by the atmosphere
Which of the following statements is correct regarding the propagation of light of different colours of white light in air?
Red light moves fastest
Blue light moves faster than green light
All the colours of the white light move with the same speed
Yellow light moves with the mean speed as that of the red and the violet light
The danger signals installed at the top of tall buildings are red in colour. These can be easily seen from a distance because among all other colours, the red light
is scattered the most by smoke or fog
is scattered the least by smoke or fog
is absorbed the most by smoke or fog
moves fastest in air
Which of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset?
Dispersion of light
Scattering of light
Total internal reflection of light
Reflection of light from the earth
The bluish colour of water in deep sea is due to
the presence of algae and other plants found in water
reflection of sky in water
scattering of light
absorption of light by the sea
When light rays enter the eye, most of the refraction occurs at the
crystalline lens
outer surface of the cornea
iris
pupil
The focal length of the eye lens increases when eye muscles
are relaxed and lens becomes thinner
contract and lens becomes thicker
are relaxed and lens becomes thicker
contract and lens becomes thinner
Which of the following statement is correct?
A person with myopia can see distant objects clearly
A person with hypermetropia can see nearby objects clearly
A person with myopia can see nearby objects clearly
A person with hypermetropia cannot see distant objects clearly