The distance between two focal points of a thin lens having focal length f is ………………
A) f
B) f/2
C) 2f
D) infinity
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When a lens of focal length f is cut in to two equal halves perpendicular to principal axis, then the focal length of each part of the lens is ………………
Correct option is B) double
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If the image distance of a convex lens of focal length 25 cm is 75 cm then the object distance is ……………………
Correct option is A) -37.5 cm
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An image is formed at distance of 30 cm from the centre of convex lens of focal length 15 cm. The distance of the object is ………………..
Correct option is C) 30 cm
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A convex lens of focal length 20 cm is cut into two halves along principal axis then focal length of each part will be …………………
Correct option is A) 20 cm
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A convex lens of focal length 20 cm is cut into two halves perpendicular to the principal axis then focal length of each part will be ……………….
Correct option is C) 40 cm
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The value of focal length of the eye lens when an object is placed at a distance of least distance of distinct vision is
Correct option is C) 2.27 cm
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The value of focal length of the eye lens when the object is between infinity and the point of least distance of distinct vision is ……………………
D) between 2.27 cm to 2.50 cm
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If a person uses a lens of -2.5 D power, then the focal length of the lens is ……………………
Correct option is C) -40 cm
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Find the focal length of the lens if the power of the lens is – 2D
Correct option is B) 50 cm
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A spherical mirror and a thin spherical lens have each a focal length of – 15 cm. The mirror and the lens are likely to be …………….
B) both are concave
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