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A convex lens of focal length 25 cm and a concave lens of focal length 20 cm are mounted coaxially separated by a distance d cm. If the power of the combination is zero, d is equal to

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Important Questions on Ray Optics

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Alpha Question Bank for Medical: Physics>Chapter 30 - Ray Optics>Exercise-1>Q 156
A convex lens of power 4D and a concave lens of power -3D are placed in contact, the equivalent power of combination is
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Alpha Question Bank for Medical: Physics>Chapter 30 - Ray Optics>Exercise-1>Q 157
Two thin lenses of power +5 D and -2 D are placed in contact with each other. The focal length of the combination will be a
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Alpha Question Bank for Medical: Physics>Chapter 30 - Ray Optics>Exercise-1>Q 158
The focal length of a plano-concave lens is - 10 cm, then its focal length when its plane surface is polished is (n=32):
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Alpha Question Bank for Medical: Physics>Chapter 30 - Ray Optics>Exercise-1>Q 159
A combination of two thin lenses with focal length f1 and f2 respectively forms an image of distant object at distance 60 cm when lenses are in contact. The position of this image shifts by 35 cm towards the combination when two lenses are separated by 10 cm. The corresponding values of f1 and f2 are:
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Alpha Question Bank for Medical: Physics>Chapter 30 - Ray Optics>Exercise-1>Q 160
A plano-convex lens (f=20 cm) is silvered at the plane surface. Now f will be
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Alpha Question Bank for Medical: Physics>Chapter 30 - Ray Optics>Exercise-1>Q 161
A luminous object is placed at a distance of 30 cm from the convex lens of focal length 20 cm. On the other side of the lens, at what distance from the lens a convex mirror of radius of curvature 10 cm be placed in order to have an upright image of the object coincident with it?
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Alpha Question Bank for Medical: Physics>Chapter 30 - Ray Optics>Exercise-1>Q 162
The plane surface of a plano-convex lens of focal length f is silvered. It will behave as
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Alpha Question Bank for Medical: Physics>Chapter 30 - Ray Optics>Exercise-1>Q 163
A concave lens of focal length 20 cm placed in contact with a plane mirror acts as a