Light Test

Result

Light Test - 9

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SHARING IS CARING

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Weekly Quiz Competition

Question 1

1 / -0

Use the following information to answer the next question.

Four persons P, Q, R and S are suffering from four different diseases, which are listed in the given table.
Person	Disease
P	Asthma
Q	Diabetes
R	AIDS
S	TB

Which of the given persons cannot donate his eyes?

P

Q

R

S

Solution

Any person, irrespective of age, social status, sex, etc., can donate his/her eyes, provided he/she is not suffering from diseases such as AIDS, hepatitis, rabies, leukaemia, tetanus, etc. It can be observed that person S is suffering from AIDS. Hence, person R cannot donate his eyes.

The correct answer is C.

Question 2
1 / -0

Which of the following precautions should TV viewers take while watching a programme?

A
Avoid direct light from the TV

B
Switch off all the lights in the room

C
Keep watching from a close distance

D
Keep the brightness of the TV very high

Solution

The brightness of a TV is very high. If it falls directly on the eye, then it can burn or damage the retina. Therefore, direct light from a television must be avoided.

The correct answer is A.
Question 3
1 / -0

Use the following information to answer the next question.

Tanvir uses his sense of touch while reading. He takes the help of a non-optical device.

Which of the following devices does Tanvir use for reading?

A
Contact lens

B
Braille stylus

C
Audio cassette

D
Magnifying glass

Solution

Visually-handicapped people use their sense of touch to read. For this, they use Braille stylus. It is a non-optical device.

The correct answer is B.

Question 4

1 / -0

Use the following information to answer the next question.

Three statements regarding the characteristics of an image formed by a plane mirror.

I The image is laterally inverted.

II The image distance from the mirror is equal to the object distance from the same.

III The image is larger than the object.

Among the given statements,

only statement I is correct

only statement III is correct

both statements I and II are correct

both statements II and III are correct

Solution

A mirror image is formed if the light rays coming from an object get reflected from the mirror. Some of the characteristics of an image formed by a plane mirror are:

(i) The image is always erect.

(ii) The image is always of the same size as the object. [Hence, statement III is incorrect.]

(iii) The image distance is always equal to the object distance with respect to the mirror. [Hence, statement II is correct.]

(iv) The image is laterally inverted. [Hence, statement I is correct.]

The correct answer is C.

Question 5
1 / -0

From which of the following objects will a regular reflection take place?

A
Brick wall

B
Table glass

C
Wooden block

D
Cardboard sheet

Solution

Regular reflections take place from smooth surfaces. In such reflections, the parallel light rays remain parallel after getting reflected from a smooth surface. Among the given objects, only a table glass has a smooth reflecting surface. Therefore, regular reflection will take place only from a table glass.

The correct answer is B.
Question 6
1 / -0

In regular reflections on a plane mirror, all parallel incident rays reflect from a

A
rough surface such that the reflected rays remain parallel

B
polished surface such that the reflected rays remain parallel

C
rough surface such that the reflected rays become divergent

D
polished surface such that the reflected rays become divergent

Solution

Plane mirrors always have smooth, polished surfaces. Regular reflection is defined only for smooth surfaces. In regular refection on a plane mirror, the angle of reflection is always equal to the angle of incidence. Therefore, parallel incident rays reflect from a polished surface with an equal angle of reflection, thereby remaining parallel.

The correct answer is B.
Question 7
1 / -0

The working of a barber’s mirror involves the phenomenon of

A
single reflection

B
multiple reflection

C
diffused reflection

D
irregular reflection

Solution

Multiple reflections take place from a set of more than one mirror. A barber’s mirror is a set of two plane mirrors. One mirror is placed in front of the viewer, while the other is placed behind him. The viewer can see the reflection of the back of his head in the mirror placed in front of him. This is possible because the light coming from the back of his head gets reflected first from the mirror placed behind him and then again, from the mirror placed in front of him. Therefore, after multiple reflections, the viewer can see the back of his head in a barber’s mirror.

The correct answer is B.

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Re-Attempt Weekly Quiz Competition

Light Test - 9

Result

Light Test - 9

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Rank

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SHARING IS CARING

Question 1

P

Q

R

S

Solution

Question 2

Avoid direct light from the TV

Switch off all the lights in the room

Keep watching from a close distance

Keep the brightness of the TV very high

Solution

Question 3

Contact lens

Braille stylus

Audio cassette

Magnifying glass

Solution

Question 4

only statement I is correct

only statement III is correct

both statements I and II are correct

both statements II and III are correct

Solution

Question 5

Brick wall

Table glass

Wooden block

Cardboard sheet

Solution

Question 6

rough surface such that the reflected rays remain parallel

polished surface such that the reflected rays remain parallel

rough surface such that the reflected rays become divergent

polished surface such that the reflected rays become divergent

Solution

Question 7

single reflection

multiple reflection

diffused reflection

irregular reflection

Solution

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