Light Test

Result

Light Test - 8

Score
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Weekly Quiz Competition

Question 1
1 / -0

Cylindrical lenses are used to cure

A
long-sightedness

B
astigmatism

C
myopia

D
presbyopia
Question 2
1 / -0

A transparent spherical structure that refracts light into the eye is called

A
pupil

B
retina

C
iris

D
cornea

Solution

The cornea is the transparent spherical structure that refracts light into the eye. It is a highly organised tissue. It contains no blood vessels to nourish or protect it against infection.
Question 3
1 / -0

The opening in the eye that regulates the amount of light entering the eye is called

A
iris

B
pupil

C
cornea

D
retina

Solution

Iris controls the amount of light entering the eye ball. It is the coloured part of the eye. It has a hole at its centre, called the pupil. Iris is responsible for changing the size of pupil according to the light conditions.
Question 4
1 / -0

The principle of persistence of vision forms the basis of working of

A
camera

B
cinema

C
spectroscope

D
periscope
Question 5
1 / -0

Figure (A), (B) and (C) show ________, ________ and ________ respectively.

A
the normal eye, the hypermetropic eye and myopic eye

B
the hypermetropic eye, the myopic eye and normal eye

C
the normal eye, the myopic eye and the hypermetropic eye

D
the myopic eye, the normal eye and the hypermetropic eye
Question 6
1 / -0

Which of the following is the relation between focal length (f) and radius of curvature (R)?

A
R =

B
R = 2f

C
R = f

D
None of these
Question 7
1 / -0

Which of the following diagrams is correct?

A

B

C

D

Solution

When light is passed through a prism, the following colours are obtained:

Red light will have minimum deviation and violet light will have maximum deviation.
Question 8
1 / -0

The least distance of distinct vision for a normal vision is about

A
25 cm

B
2.5 cm

C
25 m

D
2.5 m
Question 9
1 / -0

The relative refractive index of medium B with respect to medium A is . If the speed of light in the medium B is 2 × 10⁸, the speed of light in the medium A is

A
10⁸ m/s

B
1.5 × 10⁸ m/s

C
2 × 10⁸ m/s

D
2.25 × 10⁸ m/s
Question 10
1 / -0

The absolute refractive index is the

A
ratio compared with the refractive index of water

B
ratio compared with the refractive index of glass

C
ratio compared with the refractive index of benzene

D
ratio compared with the refractive index of vacuum
Question 11
1 / -0

The velocity of light in two different mediums of refractive indices n₁ and n₂ is v₁ and v₂, respectively. Which of the following relations will be true?

A
n₁n₂ = v₁v₂

B
n₂ =

C
n₂ = n₁

D
None of these

Solution

According to law of refraction,
Question 12
1 / -0

If the velocity of light in vacuum is 3 × 10⁸ m/s, the velocity of light in diamond (refractive index of diamond is 2.417) is

A
2 × 10⁸ m/s

B
2.1 × 10⁸ m/s

C
120 m/s

D
1.2 × 10⁸ m/s
Question 13
1 / -0

If a ray of light is incident on a plane mirror at an angle of 20^owith the mirror, what will be the angle of reflection?

A
0^o

B
70^o

C
20^o

D
90^o
Question 14
1 / -0

What is the focal length of a plane mirror?

A
Zero

B
Unity

C
Infinity

D
None of these

Solution

A plane mirror can be considered a spherical mirror of infinite radius of curvature. Focal length is half of the radius of curvature and hence it is infinity.
Question 15
1 / -0

If the magnification has a negative sign, the image is ________ and ________.

A
real, erect

B
virtual, inverted

C
real, inverted

D
virtual, erect
Question 16
1 / -0

When an object is placed between two parallel mirrors, the number of images formed will be

A
eight

B
two

C
thirty-two

D
infinite
Question 17
1 / -0

In old age, people generally have to wear spectacles for reading and writing because

A
their eye lenses start disintegrating

B
they lose the power of accommodation

C
their iris contracts

D
the lenses lose their magnifying power
Question 18
1 / -0

Which of the following options is the main difference between an eye and a camera?

A
Image on the retina is not permanent, it erases after very th of a second.

B
The eye lens can change its focal length to accommodate different objects.

C
Both (A) and (B)

D
None of these
Question 19
1 / -0

A dark muscular assembly which controls the size of the opening that regulates the amount of light entering the eye is called

A
pupil

B
retina

C
iris

D
cornea
Question 20
1 / -0

The screen of eye is called

A
pupil

B
retina

C
iris

D
cornea

Solution

Retina is the screen of eye and it is the innermost layer of the eye. The retina is a light sensitive layer at the back of the eye and covers roughly 65% of the interior surface of the eye. It contains two types of light sensitive cells called Rods and Cones.