Chapter 11 – The Human Eye and the Colourful World

Assertion: Blind spot is a small area of the retina which is insensitive to light where the optic nerve leaves the eye.
Reason: There are no rods or cones present at the junction of optic nerve and retina in the eye.

The defect of the eye in which the eyeball becomes too long is

What type of image is formed by the eye lens on the retina?

The amount of light entering the eye can be controlled by the

At noon, the Sun appears white as

Twinkling of stars is due to

The splitting of white light into different colours on passing through a prism is called

A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power

The clear sky appears blue because

One cannot see through the fog, because

Refraction of light by the earth’s atmosphere due to variation in air density is called

The deflection of light by minute particles and molecules of the atmosphere in all direction is called …………………….. of light.

The air layer of atmosphere whose temperature is less then the hot layer behave as optically

The focal length of the eye lens increases when eye muscles.

The colour that is scattered the least by the tiny particles and the atoms/ molecules of the atmosphere is

The image formed on the retina of the human eye is

When a person is myopic, he/ she can clearly see

The defect of vision in which the person is able to see distant object distinctly but cannot see nearby objects clearly is called

The defect of myopia can be corrected by using

Which of the following phenomenon contributes significantly to the reddish appearance of the sun at sunrise or sunset?

Assertion: Concave mirrors are used as reflectors in torches, vehicle head-lights and in search lights.
Reason: When an object is placed beyond the centre of curvature of a concave mirror, the image formed is real and inverted.

Assertion: The near-point of a hypermetropic eye is more than 25 cm away.
Reason: Hypermetropia is corrected using spectacles containing concave lenses.

Which of the following is a natural phenomenon which is caused by the dispersion of sunlight in the sky?

The medical condition in which the lens of the eye of a person becomes progressively cloudy resulting in blurred vision is called

The least distance of distinct vision for a normal eye is

The defect of vision in which a person cannot see the distant objects clearly but can see nearby objects clearly is called

A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power

Near and far points of a young person normal eye respectively are

Twinkling of stars is due to atmospheric

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