Human Eye and Colourful World Test

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Human Eye and Colourful World Test - 46

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Weekly Quiz Competition

Question 1
1 / -0

Why are danger signals Red Coloured

A
Human eye is most sensitive to red colour

B
Red light is scattered most by the atmosphere

C
Red light is scattered least by the atmosphere

D
Red is a terrifying colour

Solution

The red colour has the longest wavelength. So it scatters least by the particles in the atmosphere. Since red light is scattered least by the atmosphere, red is visible from large distances and is thus used for danger signals.
Question 2
1 / -0

In a beaker containing colloidal solution of sodium thiosulphate and a drop of con. sulphuric acid, light observed from side of beaker is:

A
Blue

B
Red

C
Green

D
Yellow

Solution

Colloidal solution of sodium thiosulphate consists of fine particles that mainly scatters blue light. Hence, it appears blue from the side of the beaker.
Question 3
1 / -0

Scattering of light is defined as:

A
Splitting of light into its component colours

B
Deflection of light in different directions when light is incident on extremely small particles

C
Bending of light on change of medium

D
reversal of light direction from a shiny surface

Solution

The phenomenon of scattering occurs when light is incident on very small particles and is deflected in all directions as a result of it.
Question 4
1 / -0

During dispersion through prism, red light travels fastest and violet travels slowest of all the seven colours. As a result:

A
red bends the least and violet bends the most

B
red bends the most and violet bends the least

C
both red and violet bend the least of all colours

D
both red and violet bend the most of all colours

Solution

The speed of red light is fastest and therefore there is least bending of red light whereas the speed of the violet light is slowest and hence it bends the most of all the colours. All other colours lie in between.
Question 5
1 / -0

In the context of scattering
Fine particles : ____ wavelength : : large particles : _____ wavelength

A
Long, short

B
Short, long

C
Visible, infrared

D
None of these

Solution

Fine particles scatter light of shorter wavelength at the blue end of the spectrum and larger particles scatter light of longer wavelength at the red end of the spectrum.
Question 6
1 / -0

Why astronauts see dark sky in space unlike blue sky on earth:

A
There is no day in space

B
Light is not scattered in space since there are no particles present

C
Light is reflected back from the body of the astronaut

D
Light is absorbed by the space

Solution

The sky appears blue because of the presence of the atmosphere which scatters blue light. Space has no atmosphere and no light is scattered, hence it appears dark.
Question 7
1 / -0

Why sky appears reddish orange at sunrise or sunset?

A
Sunlight suffers dispersion and only reddish light reach our eyes

B
Sunlight experiences different degree of refraction due to change in density during night

C
Sunlight has to travel longer path and blue light is scattered away, while red and yellow light is scattered least

D
The reflection of earth's surface from horizon produces reddish orange colour

Solution

White light is a combination of all the lights. During sunrise/sunset, rays have to travel larger distances and as red light scatters least, it is capable to reach our eyes while rest of the components are scattered away. Hence, sky appears reddish orange during sunrise or sunset.
Question 8
1 / -0

Blue colour of the sky is due to

A
refraction of blue light by impurities

B
refraction of blue light by water

C
scattering of light by water

D
None of the above

Solution

Explanation:
Raleigh scattering is responsible for the sky's blue. This scattering is the scattering of electromagnetic energy (of which light is one type) by particles with generally shorter wavelengths.
$$ Scattering \ \alpha \ \dfrac {1}{ \lambda^4} $$
The wavelength of blue light is shorter than the wavelength of other light, which causes more scattering. Hence sky appears blue.
Option C is correct.
Question 9
1 / -0

A myopic person cannot see clearly:

A
Near objects

B
Objects placed at the least distance of distinct vision

C
Very far objects

D
None of these

Solution

A myopic person cannot see very far objects clearly as they are unable to focus the object on the retina of their eye and the image is formed in front of the retina.
Question 10
1 / -0

Alternate inverted prisms are placed in series. Choose correct options.

A
Even number of prisms does not produce a spectrum

B
Odd number of prisms produce a spectrum

C
More the number of prisms, less is the intensity of emergent ray/spectrum

D
All of above

Solution

When a single prism is present, it splits white light into seven colours. However, combination of two inverted prisms behaves similar to a parallel glass slab and the effect is just lateral displacement of light ray. Hence, after every two prisms we get a new ray of white light. Hence, odd number of prisms produce a spectrum and even number of prisms just laterally shifts the white light.
At every surface, a part of light is reflected and a part is transmitted. Hence, after every prism light loses some intensity. Hence, more number of prisms reduces the intensity more.

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Re-Attempt Weekly Quiz Competition

Human Eye and Colourful World Test - 46

Result

Human Eye and Colourful World Test - 46

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SHARING IS CARING

Question 1

Human eye is most sensitive to red colour

Red light is scattered most by the atmosphere

Red light is scattered least by the atmosphere

Red is a terrifying colour

Solution

Question 2

Blue

Red

Green

Yellow

Solution

Question 3

Splitting of light into its component colours

Deflection of light in different directions when light is incident on extremely small particles

Bending of light on change of medium

reversal of light direction from a shiny surface

Solution

Question 4

red bends the least and violet bends the most

red bends the most and violet bends the least

both red and violet bend the least of all colours

both red and violet bend the most of all colours

Solution

Question 5

Long, short

Short, long

Visible, infrared

None of these

Solution

Question 6

There is no day in space

Light is not scattered in space since there are no particles present

Light is reflected back from the body of the astronaut

Light is absorbed by the space

Solution

Question 7

Sunlight suffers dispersion and only reddish light reach our eyes

Sunlight experiences different degree of refraction due to change in density during night

Sunlight has to travel longer path and blue light is scattered away, while red and yellow light is scattered least

The reflection of earth's surface from horizon produces reddish orange colour

Solution

Question 8

refraction of blue light by impurities

refraction of blue light by water

scattering of light by water

None of the above

Solution

Question 9

Near objects

Objects placed at the least distance of distinct vision

Very far objects

None of these

Solution

Question 10

Even number of prisms does not produce a spectrum

Odd number of prisms produce a spectrum

More the number of prisms, less is the intensity of emergent ray/spectrum

All of above

Solution

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