Part of the eye which controls the entering of light is called

1

(a)

iris

(b)

cornea

(c)

lens

(d)

retina

We can see a non-luminous object when light

1

(a)

emitted by the object falls on the eye

(b)

is reflected from the object towards our eye

(c)

completely passes through the object

(d)

gets completely absorbed by the object

In the figure of the human eye, the cornea is represented by the letter.

1

(a)

A

(b)

B

(c)

C

(d)

D

Light is falling on surfaces S₁, S₂, S₃ as shown in figure.

Surfaces on which the angle of incidence is equal to the angle of reflection is/are

1

(a)

Only S₁

(b)

S₁ and S₂

(c)

S₂ and S₃

(d)

All the three surfaces

Which of the following statements is correct regarding rods and cones in the human eye?

1

(a)

Cones are sensitive to dim light

(b)

Cones are sensitive to bright light

(c)

Rods are sensitive to bright light

(d)

Rods can sense colour

Two mirrors A and B are placed at right angles to each other as shown in Fig. below:
 
A ray of light incident on mirror A at an angle of 25° falls on mirror B after reflection. The angle of reflection for the ray reflected from mirror B would be:

1

(a)

25°

(b)

50°

(c)

65°

(d)

115°

The angle of __________ equals the angle of reflection.

1

(a)

incidence

The muscles attached to the eye lens make it thicker to see _________ objects.

1

(a)

Under special conditions

Important parts of the eye are _______, ________, _______, _______, _______ and ________.

1

(a)

cornea, iris, pupil, lens, retina, optic nerve

The impression of an image lasts for _______ second.

1

(a)

1/16

The image formed by a plane mirror is real.

1

(a) True

(b) False

The part of the eye that renders colour to it is cornea.

1

(a) True

(b) False

An unpolished or dull surface can act as a mirror.

1

(a) True

(b) False

All the rays reflected from a plane surface are not parallel. Such reflection is called diffused reflection.

1

(a) False

(b) True

On the blind spot a clear image is formed.

1

(a) True

(b) False

The distance between the object and its image formed by a plane mirror appears to be 24 cm, What is the distance between the mirror and the object?

1

(a)

Since, object distance from the mirror = Image distance from the mirror.
       
So, distance between the mirror and the object \({24\over 2}\) = 12 cm.

What makes things visible?

1

(a)

Light makes things visible.

What is lateral inversion?

1

(a)

In an image formed by a mirror the left side appears on the right side and the right side appears on the left side, this is known as lateral inversion.

What is sunlight? How many colours it consists of?

1

(a)

The sunlight is referred to as white light. It consists of seven colours.

How many kinds of nerve cells are there in retina?

1

(a)

There are two kinds of cells :
(i) Cones: Sensitive to bright light.
(ii) Rods: Sensitive to dim light.

How many times is a ray of light reflected by two plane mirrors placed parallel and facing each other?

2

(a)

Boojho while waving his hand very fast in front of his eyes, observes that his fingers appear blurred. What could be the reason for it?

2

(a)

Name the part of the eye which gives colour to the eyes.

2

(a)

Write two laws of reflection.

2

(a)

Lack of which vitamin causes troubles in our eyes? Name some food stuff to cure this problem.

2

(a)

Mention against each of the following whether regular or diffused reflection will take place when a beam of light strikes. Justify your answer in each case.
(a) Polished wooden table
(b) Chalk powder
(c) Cardboard surface
(d) Marble floor with water spread over it
(e) Mirror
(f) Piece of paper.

3

(a)

How many images of a candle will be formed, if it is placed between two parallel plane mirrors separated by 40 cm?

3

(a)

Boojho stands at A just on the side of a plane mirror as shown in figure. Can he see himself in the mirror? Also can he see the image of objects situated at P, Q and R?

3

(a)

Which part of the eye gets affected if someone is suffering from cataract? How is it treated?

3

(a)

What is Kaleidoscope? How can it be made? What are its uses?

3

(a)

Explain the process which enables us to perceive motion in a cartoon film.

5

(a)

There is a mistake in each of the following ray diagrams given as figure (a), (b), and (c). Make the necessary correction(s).

5

(a)

A man stands 10m in front of a large plane mirror. So, how far must he walk before he is 5 m away from his image?

5

(a)

How is the phenomenon of reflection used in making a kaleidoscope? What are the applications of a kaleidoscope?

5

(a)

Last Sunday morning, Pooja decided to see some bollywood movie along with her college friends. When they all entered in the cinema hall, then Pooja found some difficulty in observing the things around her but after few minutes, she got comfortable with the surroundings and she took her seat and spent 3 hrs approximately in seeing the movie. But when all of them made their exit from the all, then Pooja again left some discomfort in her eyes. At the same time, Pooja wore her goggles in order to protect herself from bright sunlight.
(a) Explain the brief that what happens to Pooja's eyes before and after seeing the movie in cinema hall.
(b) State the values showed by Pooja here.

5

(a)

Describe an activity to show that the incident ray, the reflected ray and the normal at the point of incidence, all lie in the same plane.

5

(a)