Questions

M.C.Q (1 Marks)

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39 questions · timed · auto-graded

Question 11 Mark
If the magnification of optical instrument is negative, then the image will always be formed :
Answer
(A) - Real and inverted
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Question 21 Mark
If the magnification of objective and eyepiece in a compound microscope is ' $m_o$ ' and ' $m_e$ ' respectively, then the total magnifying power $( m )$ of the microscope will be :
Answer
(C) - $m_o \cdot m_e$
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Question 41 Mark
If the refractive index of denser medium 1 relative to rare medium 2 is $n_{12}$ and the critical angle for the pair of these mediums is $i_{ c }$, then the relationship between $n _{12}$ and $i_c$ is :
Answer
(D) - $n_{12}=\frac{1}{\sin i_c}$
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Question 61 Mark
When half of a lens is wrapped in a black cloth, what will be the effect on the image formed by the lens?
Answer
(D) - The brightness of the image will decrease
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Question 71 Mark
In a microscope, the focal length of the objective lens in comparison to focal length of the eye lens is :
Answer
(A) - lees
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Question 91 Mark
A ray of light transmits from glass (refractive index $=$ $3 / 2$ ) to water (refractive index $=4 / 3$ ). The value of critical angle will be :
Answer
(C) - $\sin ^{-1}\left(\frac{8}{9}\right)$
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Question 101 Mark
When the length of the tube of a microscope is increased, the magnifying power will be :
Answer
(A) - decreases
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Question 111 Mark
The focal lengths of the objective and eye lens of a microscope are 4 cm and 8 cm respectively, and the distance of the object from the eye lens is 4.5 cm ., then the magnifying power will be :
Answer
(B) - 32
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Question 121 Mark
The focal lengths of the objective lens and the eye lens of a telescope are $f_o$ and $f_e$ respectively. Its magnifying power is approximately :
Answer
(A) - $\frac{f_o}{f_e}$
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Question 131 Mark
The power of a person's spectacle lenses is +2 D . He is suffering from which of the following defects?
Answer
(A) - From hypermetropia
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Question 151 Mark
The focal lengths of the objective and eye lens of a microscope are 4 cm and 8 cm respectively and the distance of the object from the objective is 4.5 cm , then the magnifying power will be :
Answer
(B) - 32
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Question 161 Mark
When a bi-convexo lens of glass with refractive index 1.47 is immersed in a liquid, then it behaves like a plane glass sheet, it means that the refractive index of the liquid is :
Answer
(A) - equivalent to the refractive index of glass
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Question 171 Mark
The magnifying power of a telescope is $M$. If the focal length of the eye lens is doubled, then the magnifying power will be :
Answer
(B) - $\frac{1}{2} M$
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Question 181 Mark
If the refractive index of a prism is $\sqrt{2}$ and the angle of refraction is $60^{\circ}$, then its minimum deviation angle will be :
Answer
(B) - $30^{\circ}$
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Question 191 Mark
The radii of curvature of a convex lens are 15 cm and 30 cm respectively. Its refractive index is 1.5 . The focal length of the lens will be :
Answer
(A) - 20 cm
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Question 201 Mark
A concave mirror of focal length f, has formed the image of magnification m, the distance of the object from the mirror is :
Answer
(A) - $\frac{(m-1) f}{m}$
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Question 211 Mark
$\lambda$ ray of light passes through a prism of refractive index $\sqrt{2}$ in such a way that its angle of incidence is twice of the angle of refraction and there is minimum deviation in the ray. The angle of the prism will be :
Answer
(B) - $90^{\circ}$
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Question 231 Mark
The focal length of a convex lens is 2.5 cm. The value of its maximum magnifying power will be :
Answer
(C) - 11
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Question 241 Mark
Which of the following formula is correct for a spherical lens?
Answer
(B) - $\frac{1}{f}=\frac{1}{v}-\frac{1}{u}$
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Question 251 Mark
When a distant object is viewed through an astronomical telescope, its image will be :
Answer
(B) - inverted
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Question 271 Mark
If $\angle i=60^{\circ}$ and $\angle r=90^{\circ}$ then the refractive index ${ }_1 n_2$ will be :
Answer
(A) - $\frac{\sqrt{3}}{2}$
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Question 281 Mark
For the total internal reflection from any medium to vacuum, critical angle is $30^{\circ}$ then speed of light will be :
Answer
(B) - $1.5 \times 10^8 m / s$
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Question 291 Mark
A light ray incident on a surface of refractive index $n$, which is separating this medium from air. The angle of incidence is $45^{\circ}$. For what value of $n$ can this ray have total internal reflection?
Answer
(C) - $n=1.50$
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Question 301 Mark
A compound lens has been manufactured by combining lenses of power +2.50 D and -3.75 D . The value of its focal length in cm will be :
Answer
(C) - $-80$
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Question 311 Mark
The focal length of a concave mirror is 10 cm. On placing an object at 10 cm in front of the mirror, its image will be formed:
Answer
(A) - at infinity
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Question 331 Mark
If a ray of light is incident normally on a plane mirror then the value of the angle of reflection is:
Answer
(C) $0^{\circ}$
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Question 351 Mark
The radius of curvature of a concave mirror is 0.80 cm, its focal length in meters will be :
Answer
(A) - 0.40 meter
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Question 381 Mark
For which colour, the angle of deviation is maximum when light enters into glass from air?
Answer
(D) - Violet
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Question 391 Mark
Only paraxial rays are used in image formation by spherical mirror; because this:
Answer
(D) - forms a point image of a point object.
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