# Topic: Ray Optics and Optical Instruments (Test 1)

Topic: Ray Optics and Optical Instruments
Q.1
Light rays from a point object
A. radiate only to the side
C. radiate only at the front
Explaination / Solution:
No Explaination.

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Q.2
According to Cartesian sign convention.
A. all distances are measured from the bottom of the mirror or the lens
B. all distances are measured from infinity
C. all distances are measured from the pole of the mirror or the optical centre of the lens
D. all distances are measured from the top of the mirror or the lens
Explaination / Solution:
No Explaination.

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Q.3
According to Cartesian sign convention the heights measured
A. rightwards with respect to x-axis and normal to the principal axis (x-axis) of the mirror/lens are taken as positive
B. leftwards with respect to x-axis and normal to the principal axis (x-axis) of the mirror/lens are taken as positive
C. downwards with respect to x-axis and normal to the principal axis (x-axis) of the mirror/lens are taken as positive
D. upwards with respect to x-axis and normal to the principal axis (x-axis) of the mirror/lens are taken as positive
Explaination / Solution:
No Explaination.

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Q.4
Focal length of a mirror is given by
A. f = R, R=radius of curvature
B. f = ${\mathrm{R}}^{2}$, R=radius of curvature
C. f = R/2, R=radius of curvature
D. f = R/4, R=radius of curvature
Explaination / Solution:
No Explaination.

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Q.5
According to the mirror equation
A. 1f=1u+2v
B. 1f=1u+1v
C. 1f=2u+1v
D. 2f=1u+1v
Explaination / Solution:
No Explaination.

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Q.6
Refraction is
A. Reversal of direction of propagation of light
B. Change of direction of propagation of light at the interface of two media as light passes from one medium to another
C. The change of direction of propagation of light
D. None of the above
Explaination / Solution:
No Explaination.

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Q.7
According to Snellâ€™s law
A. The ratio of the sine of the angle of incidence to the sine of angle of refraction is constant
B. The ratio of the angle of incidence to the angle of refraction is constant
C. The ratio of the cosine of the angle of incidence to the cosine of angle of refraction is constant
D. The ratio of the tangent of the angle of incidence to the tangent of angle of refraction is constant
Explaination / Solution:
No Explaination.

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Q.8
For a rectangular slab, refraction takes place at
A. One interfaces
B. Four interfaces
C. Three interfaces
D. Two interfaces
Explaination / Solution:
No Explaination.

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Q.9
Total internal reflection can take place only if light is travelling from
A. Rarer to denser medium
B. any two media
C. Denser to rarer medium
D. No two media
Explaination / Solution:
No Explaination.

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Q.10
Total internal reflection can take place only if
A. incidence angle = 1/ = refractive index travelling from 2 to 1
B. tan(incidence angle) = 1/ = refractive index travelling from 2 to 1
C. sin(incidence angle) = 1/ = refractive index travelling from 2 to 1
D. cos(incidence angle) = 1/ = refractive index travelling from 2 to 1