Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 80

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Important Questions on Ray Optics and Optical Instruments

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 81

A double concave thin lens made out of glass

(μ = 1.5)

have radii of curvature

500 cm

. This lens is used to rectify the defect in vision of a person. The far point of the person will be at

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 82

A convex lens forms a real image

16 mm

long on a screen. If the lens is shifted to a new position without disturbing the object or the screen then again a real image of length

81 mm

is formed. The length of the object must be

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 83

A point object is moving with speed $u_{0}$ at a position somewhere between $2 F$ and $F$ in front of a convex lens. The speed of its image is

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 84

The minimum magnifying power of telescope is

M

. If the focal length of its eye lens is halved, the magnifying power will become

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 85

An object is placed in front of two convex lenses one by one at a distance

u

from the lens. The focal lengths of the lenses are

30 cm

and

15 cm

respectively. If the size of image formed in the two cases is same, then

u

is

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 86

If $R_{1}$ and $R_{2}$ are the radii of curvature of the spherical surfaces of a thin lens and $R_{1} > R_{2}$ , then this lens can

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 87

The focal length of a thin lens in vacuum is

f

. If the material of the lens has

μ = \frac{3}{2}

, its focal length when immersed in water of refractive index

\frac{4}{3}

will be

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 88

For an astronomical telescope having

f_{o}

as the focal length of the objective and

f_{e}

as the focal length of the eyepiece, the length of the telescope tube in normal adjustment is