Why does diamong sparkle?

The diamond has a very high refractive index 2 . 45 and hence low critical angle (about 24 ° ) Apart from this, it is cut in a special manner so that most of the light incident on it any internal faces have a higher angle of incidence than its critical angle This makes the light suffers multiple internal reflections from its inner faces. This makes the diamond shine.

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Two thin lenses of focal lengths $20 cm$ and $- 20 cm$ are placed in contact with each other. The combination has a focal length equal to

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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>EXERCISE>Q 24

If in a plano-convex lens the radius of curvature of the convex surface is

10 cm

and the focal length of the lens is

30 cm

, the refractive index of the material of the lens will be :

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 19

A glass concave lens is placed in a liquid in which it behaves like a convergent lens. If the refractive indices of glass and liquid with respect to air are

{}_{a}μ_{g}

and

{}_{a}μ,

respectively, then

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 20

The diameter of aperture of a plano-convex lens is

6 cm

and its maximum thickness is

3 mm .

If the velocity of light in the material of the lens is

2 \times 10^{8} m / s,

its focal length is (approximately)

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 21

Two plano-convex lenses of equal focal lengths are arranged as shown

Question Image
The ratio of the combined focal lengths is

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 22

When an object is at a distance

u_{1}

and

u_{2}

from a lens, real image and a virtual image is formed respectively having same magnification. The focal length of the lens is

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 23

A concave lens of focal length

f

produces an image

(1 / x)

of the size of the object. The distance of the object from the lens is

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 24

A thin equiconvex glass lens of refractive index

1.5

has power of

5 D .

When the lens is immersed in a liquid of refractive index

μ,

it acts as a divergent lens of focal length

100 cm .

The value of

μ

of liquid is

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 25

A convex lens of focal length

100 cm

and a concave lens of focal length

10 cm

are placed coaxially at a separation of

90 cm .

If a parallel beam of light is incident on convex lens, then after passing through the two lenses the beam

Two thin lenses of focal lengths 20 cm and -20 cm are placed in contact with each other. The combination has a focal length equal to

Important Questions on Ray Optics and Optical Instruments

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Two thin lenses of focal lengths $20 cm$ and $- 20 cm$ are placed in contact with each other. The combination has a focal length equal to