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question_answer1)
Which of the following is called converging lens?
A)
Convex lens done
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B)
Concave lens done
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C)
Plane lens done
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D)
Any lens done
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E)
None of these done
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question_answer2)
Which of the following convex lenses will have greater magnifying power?
A)
Convex lens with focal length 10 done
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B)
Convex lens with focal length 20 done
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C)
Convex lens with focal length 15 done
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D)
Convex lens with focal length 25 done
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E)
None of these done
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question_answer3)
When an object is placed at the focus of the convex lens, the image will be formed at:
A)
Infinity done
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B)
Twice the focal length done
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C)
Focus of the lens done
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D)
Between the optical centre of] lens and its Focus done
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E)
None of these done
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question_answer4)
An object is placed at ____ distance from a convex lens of the focal length 10 cm to produce a real and smaller image.
A)
8 cm done
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B)
10 cm done
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C)
20 cm done
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D)
25 cm done
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E)
None of these done
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question_answer5)
If an incident ray passes through the centre of curvature of a spherical mirror the reflected ray will be:
A)
Pass through the pole done
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B)
Pass through the focus done
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C)
Retrace its path done
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D)
Parallel to the principal axis done
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E)
None of these done
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question_answer6)
Which of the following types of images can be formed by a concave lens?
A)
An inverted magnified image done
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B)
An erect magnified image done
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C)
An erect diminished image done
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D)
An inverted diminished image done
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E)
None of these done
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question_answer7)
At what distance an object from a concave mirror having focal length of 20 cm should be placed so that the mirror forms a virtual image at 10 cm from the mirror?
A)
\[-12\text{ }cm\] done
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B)
\[-6.6\text{ }cm\] done
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C)
\[-30\text{ }cm\] done
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D)
\[-25\text{ }cm\] done
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E)
None of these done
clear
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question_answer8)
Which of the following is the power of convex lens having focal length 20 cm?
A)
4 done
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B)
6 D done
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C)
20 D done
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D)
5 D done
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E)
None of these done
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question_answer9)
What is the focal length of lens having power + 2D?
A)
20 cm done
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B)
25 cm done
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C)
40 cm done
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D)
50 cm done
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E)
None of these done
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question_answer10)
The stars appear twinkling on a clear night due to:
A)
Reflection of light done
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B)
Refraction of light done
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C)
Scattering of light done
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D)
Both a and b done
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E)
None of these done
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question_answer11)
The muscles of the iris control the:
A)
Focal length of the eye-lens done
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B)
Amount of light entering the eye done
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C)
Shape of the cyrstalline lens done
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D)
Optic nerve done
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E)
None of these done
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question_answer12)
When the eye is focused on an object very far away, then the focal length of the eye lens is:
A)
Maximum done
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B)
Minimum done
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C)
Half its maximum focal length done
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D)
Equal to that of the crystalline done
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E)
None of these done
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question_answer13)
Other names for myopia is:
A)
Near - sightedness done
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B)
Short- sightedness done
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C)
Long - sightedness done
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D)
Both [a] and [b] done
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E)
None of these done
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question_answer14)
Which phenomenon of light makes the sky look blue?
A)
Reflection done
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B)
Refraction done
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C)
Scattering done
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D)
Dispersion done
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E)
None of these done
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question_answer15)
In the dispersion of white light, which of the following colour bends the least?
A)
Violet done
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B)
Red done
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C)
Blue done
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D)
Green done
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E)
None of these done
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question_answer16)
The farthest point upto which the eye can see properly is called:
A)
Least distance of clear vision done
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B)
Far point done
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C)
Near point done
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D)
Long- sightedness done
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E)
None of these done
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question_answer17)
If the radius of curvature of a spherical mirror is 25 cm, what is its focal length?
A)
25 cm done
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B)
20 cm done
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C)
12.5 cm done
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D)
50 cm done
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E)
None of these done
clear
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question_answer18)
A highly enlarged image is obtained when:
A)
The object is placed at the focus in front of a convex mirror. done
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B)
The object is placed at the infinity in front of concave mirror. done
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C)
The object is placed at the focus in front of a concave mirror. done
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D)
The object is placed at the centre of curvature in front of a concave mirror. done
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E)
None of these done
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question_answer19)
Which of the following options is correct when an object of size 1 cm is placed at a distance of 20 cm from a concave mirror of focal length 15 cm.
A)
Nature: real and smaller, Image distance = 60 cm done
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B)
Nature: virtual and enlarged, Image distance = 60 cm done
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C)
Nature: real and enlarged, Image distance = 60 cm done
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D)
Nature: virtual and smaller, Image distance = 60 cm done
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E)
None of these done
clear
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question_answer20)
Which of the following statements is correct?
A)
Hypermetropia is corrected by using convex lens. done
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B)
Myopia is corrected by using concave lens. done
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C)
Hypermetropia is also known as long-sightedness. done
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D)
All the above done
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E)
None of these done
clear
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question_answer21)
A convex lens of focal length 4 cm forms a real image and same size as the object. The object is :
A)
Between F and 2F done
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B)
At 2F done
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C)
At infinity done
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D)
At focus done
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E)
None of these done
clear
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question_answer22)
Light enters from air into a glass plate having refractive index 2. What is the speed of light in glass? (The speed of light in vacuum is \[3\times l08\text{ }m/s\]).
A)
\[2\times {{10}^{8}}\text{ }m/s\] done
clear
B)
\[3\times {{10}^{5}}\text{ }m/s\] done
clear
C)
\[1.5\times {{10}^{8}}\text{ }m/s~~~~\] done
clear
D)
\[1.8\times {{10}^{5}}\text{ }m/s\] done
clear
E)
None of these done
clear
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question_answer23)
Which one of the following does not involve the use of convex lens?
A)
Making a simple camera. done
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B)
Correcting the myopic eye defect. done
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C)
Using as a magnifying glass. done
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D)
All the above done
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E)
None of these done
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question_answer24)
An object is placed at a distance of 25 cm from a convex lens of focal length 10 cm. The image produced will be:
A)
Magnified and real done
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B)
Magnified and virtual done
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C)
Of the same size as the object done
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D)
Smaller and real done
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E)
None of these done
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question_answer25)
Which of the following is used as an eye-lens in Galilean telescope?
A)
Concave mirror done
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B)
Convex Mirror done
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C)
Convex lens done
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D)
Concave lens done
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E)
None of these done
clear
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question_answer26)
Which of the following statements is incorrect?
A)
The focal length of a convex lens is considered positive done
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B)
The focal length of convex mirror is considered positive done
clear
C)
The power of convex lens is always negative done
clear
D)
All the above done
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E)
None of these done
clear
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question_answer27)
When light is dim, the pupil becomes:
A)
Black done
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B)
Small done
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C)
Large done
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D)
White done
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E)
None of these done
clear
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question_answer28)
In which of the following cases concave mirror is not used?
A)
To magnify the objects done
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B)
In make - up mirror done
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C)
In dentist's mirror done
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D)
As rear - view mirror in vehicles done
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E)
None of these done
clear
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question_answer29)
Find the refractive index of a substance L. If the angle of incidence is \[72{}^\circ \] and the angle of refraction is \[90{}^\circ \]. (\[sin\text{ }72{}^\circ =0.951\])
A)
1.48 done
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B)
0.951 done
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C)
1.951 done
clear
D)
2.48 done
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E)
None of these done
clear
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question_answer30)
A pencil of 5 cm long is placed at a distance of 12 cm from a convex lens. Assuming it to be perpendicular to the principal axis, calculate the size of the image formed if the focal length of the lens is 8 cm.
A)
20 cm done
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B)
15 cm done
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C)
10 cm done
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D)
12 cm done
clear
E)
None of these done
clear
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question_answer31)
The process of adjustment of focal length of eye lens is known as :
A)
Image formation done
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B)
Accommodation done
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C)
Lateral inversion done
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D)
Dispersion done
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E)
None of these done
clear
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question_answer32)
In which of the following cases we get a virtual, erect and magnified image?
A)
When the magnification produced by a spherical lens is + 2. done
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B)
When the magnification produced by a spherical lens is + 0.75. done
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C)
When the height of image is negative and height of the object is positive in case of concave mirror. done
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D)
All the above done
clear
E)
None of these done
clear
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question_answer33)
Which of the following statements is correct?
A)
A substance having higher refractive index is optically rarer. done
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B)
A substance having lower refractive index is optically denser. done
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C)
Kerosene is optically denser than water. done
clear
D)
All the above done
clear
E)
None of these done
clear
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question_answer34)
???????? is the instrument used to measure the power of a spectacle.
A)
Dioptremeter done
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B)
Biometer done
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C)
Ammeter done
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D)
Anemometer done
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E)
None of these done
clear
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question_answer35)
Which of the following statements is correct?
A)
At blind spot in the eye is a place where more number of rods are present. done
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B)
Focal length of the lens present in our eye is controlled by cornea. done
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C)
The front part of the eye is called iris. done
clear
D)
A virtual image is formed on retina present in human eye done
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E)
None of these done
clear
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question_answer36)
The amount of light entering the eye is controlled by:
A)
Cornea done
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B)
Iris done
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C)
Aqueous humour done
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D)
Vitreous humour done
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E)
None of these done
clear
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question_answer37)
When an object is placed at a distance of 36 cm from a concave spherical mirror, the magnification produced is \[-\text{ }1/3\]. If image is formed at the same place where the object should be placed to get a magnification of \[-\text{ }1/4\]?
A)
\[-\text{ }12\,\,cm\] done
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B)
\[-\text{ 48}\,\,cm\] done
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C)
\[-\text{ 36}\,\,cm\] done
clear
D)
\[-\text{ 50}\,\,cm\] done
clear
E)
None of these done
clear
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question_answer38)
Which of the following statements is correct if the magnification produced by the mirror is \[-\text{ }3\]?
A)
The image is erect and virtual. done
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B)
The size of the image is one-third the size of the object. done
clear
C)
The size of the image is thrice the size of the object. done
clear
D)
All the above done
clear
E)
None of these done
clear
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question_answer39)
Magnification produced by a plane mirror is always equal to one because:
A)
Size of the image is twice the size of the object. done
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B)
Size of the object is twice the size of the image. done
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C)
Size of the object is equal to the size of the image. done
clear
D)
Size of the image formed does not depend upon the size of the object. done
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E)
None of these done
clear
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question_answer40)
If the refractive index of glass is 1.5. Then the speed of light in glass is :
A)
\[2\times {{10}^{8}}m\,/s\] done
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B)
\[3\times {{10}^{8}}m\,/s\] done
clear
C)
\[1.071\times {{10}^{8}}m\,/s\] done
clear
D)
\[1.28\times {{10}^{8}}m\,/s\] done
clear
E)
None of these done
clear
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