Light Test

Result

Light Test - 11

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Weekly Quiz Competition

Question 1
1 / -0

A series of fast-moving still pictures can create an illusion of movement because:

A
The eye can focus on very rapidly changing pictures

B
The eye is quicker than the brain

C
The eye can separate two images only when the interval of separation between them is one-sixteenth of a second

D
The optical cortex can see through the rapidly moving images

Solution

The impression of an image does not vanish immediately from the retina. It persists there for about one-sixteenth of a second. So, if still images of a moving object are flashed on the eye at a rate faster than 16 per second, then the eye perceives this object as moving.
Question 2
1 / -0

....... is used in submarines to see object above the water surface.

A
Microscope

B
periscope

C
solar panel

D
all

Solution

Periscope is used in submarines to see the objects above the water surface.
Question 3
1 / -0

Plane mirrors are used in the construction of :

A
Periscope

B
Solar cooker

C
Telescope

D
Microscope

Solution

Periscopes are made using plane mirrors.
Question 4
1 / -0

According to the law of reflection:

A
$$ i/ r =$$ constant

B
$$\sin$$ $$i/\sin$$ $$r =$$ constant

C
$$i+r=$$ constant

D
$$i=r$$

Solution

According to the law of reflection, the angle of incidence ($$i$$) is equal to the angle of reflection ($$r$$).
Question 5
1 / -0

________ is used to see enemy movements from trenches.

A
Microscope

B
Periscope

C
Both $$A$$ and $$B$$

D
None of these

Solution

A periscope is defined as an instrument used for observing over, around, or through an obstacle or object which is prevented by a direct line of sight. Periscope is used to see enemy movements from trenches.
Question 6
1 / -0

.................. ray is the ray of light striking the surface of a reflector.

A
Incident

B
refracted

C
reflected

D
All the above

Solution

An incident ray is the ray of light that strikes the surface of a reflector.
Question 7
1 / -0

Periscope is used to :

A
magnify extremely small objects into bigger images

B
observe the distant images such as planets and stars

C
analyse the spectrum formed by the sunlight

D
view objects placed at a higher level from a position at lower level

Solution

Periscope is used to view objects placed at a higher level from a position at a lower level.
Question 8
1 / -0

The phenomenon of light coming back after hitting a smooth plane surface is called :

A
Reflection

B
Refraction

C
Dispersion

D
Total internal reflection

Solution

Reflection is the phenomenon of light coming back after hitting a smooth plane surface.
Option A
Question 9
1 / -0

When the angle between two plane mirrors is $$60°$$, how many images will be formed by the mirrors?

A
5

B
6

C
7

D
8

Solution

Number of images formed when two plane mirrors are kept at an angle $$q $$ degrees is:
$$\dfrac { 360 }{ q } -1$$
i.e., $$\dfrac { 360 }{ 60 } -1 = 6 - 1 = 5$$
Question 10
1 / -0

Plane mirrors are arranged at an angle to get a number of colored images in :

A
Periscope

B
Kaleidoscope

C
Telescope

D
Thermoscope

Solution

A) Periscope is an apparatus consisting of a tube attached to a set of mirrors or prisms, by which an observer (typically in a submerged submarine or behind a high obstacle) can see things that are otherwise out of sight.

B) Kaleidoscope is a toy consisting of a tube containing mirrors and pieces of colored glass or paper, whose reflections produce changing patterns when the tube is rotated. Here, Kaleidoscope plane mirrors are arranged at an angle to get a number of colored images.

C) Telescope is an optical instrument designed to make distant objects appear nearer, containing an arrangement of lenses, or of curved mirrors and lenses, by which rays of light are collected and focused and the resulting image gets magnified.

D) Thermoscope is an instrument that shows changes in the temperature of a substance by noting changes in the volume of the substance.

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Re-Attempt Weekly Quiz Competition

Light Test - 11

Result

Light Test - 11

Score

-

Rank

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SHARING IS CARING

Question 1

The eye can focus on very rapidly changing pictures

The eye is quicker than the brain

The eye can separate two images only when the interval of separation between them is one-sixteenth of a second

The optical cortex can see through the rapidly moving images

Solution

Question 2

Microscope

periscope

solar panel

all

Solution

Question 3

Periscope

Solar cooker

Telescope

Microscope

Solution

Question 4

$$ i/ r =$$ constant

$$\sin$$ $$i/\sin$$ $$r =$$ constant

$$i+r=$$ constant

$$i=r$$

Solution

Question 5

Microscope

Periscope

Both $$A$$ and $$B$$

None of these

Solution

Question 6

Incident

refracted

reflected

All the above

Solution

Question 7

magnify extremely small objects into bigger images

observe the distant images such as planets and stars

analyse the spectrum formed by the sunlight

view objects placed at a higher level from a position at lower level

Solution

Question 8

Reflection

Refraction

Dispersion

Total internal reflection

Solution

Question 9

5

6

7

8

Solution

Question 10

Periscope

Kaleidoscope

Telescope

Thermoscope

Solution

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