MCQ Questions for Class 10 Physics Human Eye And Colorful World Quiz 8

A person can see clearly up to 3 metres what should be the power of the lens in his spectacles so that he could see clearly up to 12 metres.

0%
0.25 D
0%
-0.25 D
0%
0.5 D
0%
- 0.75 D

Explanation

Answer is B.

The lens equation is given as

$\displaystyle \frac{1}{u}+ \frac{1}{v} = \frac{1}{f}$

$\displaystyle \frac{1}{1200} + \frac{1}{-300} - \frac{1}{f}$ (u and v are in cm)

The negative sign is due negative value of the image distance of the concave lens.

$f = - 400\ cm$
Power

$=\displaystyle \frac{100}{f}$ in cm.
So,

$\displaystyle \frac{100}{-400} = - 0.25 D$ .
Hence, the power of the lens in his spectacles is -0.25D.

A child was prescribed the following lenses for his spectacles by the optician:Left eye: + 2.50D, Right eye: +1.25D .The child has a defect of vision called:

0%
Presbyopia
0%
Myopia
0%
Hypermetropia
0%
Astigmatism

If the optician's prescription for the spectacles reads: Left eye: -3.00 D, Right eye: -3.5 D then the person is suffering from the defect of vision called:

0%
Astigmatism
0%
Myopia
0%
Presbyopia
0%
Hypermetropia

At sun rise or at sun set the sun appears to be reddish while at mid day it looks white. This is because

0%
Scattering due to dust particles and air molecules causes this phenomenon
0%
The sun is cooler at sun rise or at sunset
0%
Refraction causes this phenomenon
0%
Diffraction sends red rays to the earth at these times

A person cannot see objects clearly which are nearer than 75 cms from his eyes, the disease he is suffering from is:

0%
Astigmatism
0%
Myopia
0%
Hypermetopia
0%
Presbyopia

Long-sightedness is to hypermetropia as short-sightedness is to :

0%
myopia
0%
focusing
0%
astigmatism
0%
accomodation

Figure (a), (b), and (c) respectively, indicate the point of focus in case of :

0%
The normal eye, the hypermetropic eye and myopic eye
0%
The hypermetropic eye, the mypoic eye and the normal eye
0%
The normal eye, the myopic eye and the hypermetropic eye
0%
The myopic eye, the normal eye and the hypermetropic eye

Long-sightedness is caused by the eyeball being too short. It can be corrected by the use of a :

0%
convergent lens
0%
plane mirror
0%
divergent lens
0%
concave mirror

Hypermetropia is due to the ________ of the eye.

0%
low converging power
0%
low diverging power
0%
high converging power
0%
high diverging power

Identify the correct statement from the following

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The setting sun appears higher in the sky than that of glass
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In glass, red light travels faster than violet light
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The refractive index of diamond is greater than that of glass
0%
Refractive index of a material is greater for red light than that of violet light.

A person cannot see the objects clearly placed at distance more than

$40\ cm$ . He is advised to use lens of power:

0%
$-2.5\ D$
0%
$+2.5\ D$
0%
$-6.25\ D$
0%
$+1.5\ D$

Explanation

That lens should be given to the person which forms the image of an object at infinity at distance 40 cm in front of the eye.

Hence,

$u=-\infty$ and

$v=-40cm$

Now,

$\dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}$

$\implies \dfrac{1}{f}=\dfrac{-1}{40}-\dfrac{1}{-\infty}$

$\implies f=-40cm$

$P=\dfrac{100}{f(cm)}=\dfrac{-100}{40}$

$\implies P=-2.5D$

Answer-(A).

Reflection of the sunlight from the upper layers of the Earth's atmosphere causes

0%
days and nights
0%
tides
0%
eclipses
0%
twilight

A near sighted person cannot see distinctly beyond

$50 cm$ from his eye. The power in diopter of spectacle lenses which will enable him to see distant objects clearly is:

0%
+50 D
0%
-50 D
0%
+2 D
0%
-2 D

Explanation

When a person cannot see far situated object we assume object distance to infinity.

Then image distance be v = -50cm

$u=\infty \\ v=-50cm$

then,

$\dfrac { 1 }{ f } =\dfrac { 1 }{ v } -\dfrac { 1 }{ u } \\ \dfrac { 1 }{ f } =-\dfrac { 1 }{ 50 } \\ f=-50cm=-0.5m$ (concave lens)

$power=\dfrac { 1 }{ f } =\dfrac { 1 }{ 0.5 } =-2D$

Figures (a), (b), (c) and (d) respectively correspond to

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The short-sighted eye, the correction of long-sight, the long-sighted eye and the correction of short-sight
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The short-sighted eye, the correction of short-sight, the long-sighted eye and the correction of long-sight
0%
The long-sighted eye, correction of short-sight, the short-sighted eye and the correction of long-sight
0%
The long-sighted eye, the correction of long-sight, the long-sighted eye and the correction of short-sight

The figure above shows the eye suffering from :

0%
hypermetropia
0%
myopia
0%
astigmatism
0%
short-sightedness

Which of the following lens is used to minimise hypermetropia ?

0%
Convex lens
0%
Concave lens
0%
Cylindrical lens
0%
Planar lens

Explanation

A person with hypermetropia can see distant objects clearly but cannot see nearby objects distinctly. The near point, for the person, is farther away from the normal near point

$(25\ cm)$ . This is because the light rays from a closeby object are focused at a point behind the retina. This defect can be corrected by using a convex lens of appropriate power

The film of camera is compared to which part of human eye?

0%
Lens
0%
Retina
0%
Iris
0%
Choroid

The sky is blue because

0%
There is more blue light in the sunlight
0%
Of scattering of sunlight by air molecules in the atmosphere
0%
Of scattering of sunlight by dust particles in the atmosphere
0%
Other colours are absorbed by heavenly bodies

Explanation

When a parallel beam of light passes through any medium full of molecules and other particles, light gets scattered in every possible direction due to presence of such molecules, dust particles etc.

Also,

Probability of scattering is proportional to

$\dfrac{1}{\lambda^4}$

therefore, blue scatters more as it has smaller wavelength.

1404474_372753_ans_85650a9c65fb4ce88f93742af076544a.png

Which of the following colour of light undergoes the maximum deviation while passing a glass prism?

0%
Red
0%
Blue
0%
Violet
0%
Green

Explanation

Violet undergoes maximum deviation while passing through a prism because it has least wavelength , as we know,

We know,

$\nu\times \lambda=c$

Frequency is a constant quantity.So velocity of VIOLET light will be least in the medium.

also,

$\mu=\dfrac{velocity\ of\ light\ in\ vacuum}{velocity\ of\ light\ in\ a\ medium}$

so, refractive index property for violet will be maximum and it will refract the most. and will have the greatest deviation.

The angle between the original path of the incident ray and the emergent ray coming out of a prism is called angle of

0%
incidence
0%
reflection
0%
prism
0%
deviation

At sunrise or sunset, the sun appears to be reddish white. This is because :

0%
The sun is colder at sunrise or at sunset
0%
Diffraction sends red rays to the earth at these times
0%
Refraction causes this phenomenon
0%
Scattering due to dust particles and air molecules causes the phenomenon
0%
None of these

The figure above shows the eye suffering from :

0%
hypermetropia
0%
myopia
0%
astigmatism
0%
far-sightedness

In hypermetropia, the image of near object is formed :

0%
Before the retina
0%
On retina
0%
Behind the retina
0%
Above the retina

The earth's atmosphere is transparent for the visible light.

0%
True
0%
False

Which of the following lens is used to minimise myopia ?

0%
Convex lens
0%
Concave lens
0%
Cylindrical lens
0%
Planar lens

Mirages are observed in deserts due to the phenomenon of

0%
Interference of light and reflection of light
0%
Total internal reflection of light and refraction of light
0%
Scattering of light and dispersion of light
0%
Double refraction of light

Angle of deviation is between :

0%
Real and virtual image
0%
Incident and emergent ray
0%
Plane of reflection and plane of incidence
0%
None of the above

Which of the following is not a characteristics of a concave lens?

0%
Thick at the edges and thin in the middle.
0%
Used to correct shortsightedness
0%
A diverging lens
0%
Used to correct longsightedness

In myopia, the image of distant object is formed :

0%
Before the retina
0%
On the retina
0%
Behind the retina
0%
Above the retina

The least distance of distinct vision for a defective eye is

$75$ cm. What should be the focal length of the lens which will be used to read a book clearly at

$25$ cm?

0%
$75\ cm$
0%
$25\ cm$
0%
$37.5\ cm$
0%
$150\ cm$

Explanation

Given,

Near point of defective (hypermetropic eye)

$= 75\ cm$

Near point of normal eye

$= 25\ cm$

object distance,

$u = -25\ cm$

image distance,

$v = -75\ cm$

Using lens formula,

$\dfrac{1}{v} - \dfrac{1}{u} = \dfrac{1}{f}$

$\dfrac{1}{f} = \dfrac{1}{-75} - \dfrac{1}{-25} = \dfrac{-1 + 3}{75}$

$\dfrac{1}{f} = \dfrac{2}{75}$

$f = 37.5\ cm$

CBSE Questions for Class 10 Physics Human Eye And Colorful World Quiz 8 - MCQExams.com

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Practice Class 10 Physics Quiz Questions and Answers

CBSE Questions for Class 10 Physics Human Eye And Colorful World Quiz 8 - MCQExams.com

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Practice Class 10 Physics Quiz Questions and Answers

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