An object is placed at a distance of f 2 from a convex lens. The image will be

At one of the foci, virtual and double its size

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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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 8

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A narrow, paraxial beam of light is converging towards a point I on a screen. A plane parallel plate of glass of thickness $t,$ and refractive index $μ$ is introduced in the path of the beam. The convergence point is shifted by

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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 9

The length of a vertical pole at the surface of a lake of water

(μ = \frac{4}{3})

is

24 cm .

Then to an under-water fish just below the water surface the tip of the pole appears to be

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 10

A ray of light strikes a glass plate at an angle of

60 °

. If the reflected and refracted rays are perpendicular to each other, the index of refraction of glass is,

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 11

A microscope is focused on a coin lying at the bottom of a beaker. The microscope is now raised up by

1 cm .

To what depth should the water be poured into the beaker so that coin is again in focus? (Refractive index of water is

\frac{4}{3})

.

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 12

Two transparent media A and B are separated by a plane boundary. The speed of light in medium A is

2 \times 10^{8} m s^{- 1}

and in medium B is

2.5 \times 10^{8} m s^{- 1}

. The critical angle for which a ray of light going from A to B is totally internally reflected is

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 13

Which of the following is possible application of fibre optics ?

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 14

An object is placed at a distance of

\frac{f}{2}

from a convex lens. The image will be

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 15

The least distance between a point object and its real image formed by a convex lens of focal length

F

is

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Gamma Question Bank for Medical Physics>Chapter 26 - Ray Optics and Optical Instruments>Assignment>Q 16

The plane faces of two identical plano-convex lenses each having a focal length of

40 cm

are pressed against each other to form a usual convex lens. The distance from this lens, at which an object must be placed to obtain a real, inverted image with magnification one is