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A bulb is placed at a depth of 2sqrt7cm ...

A bulb is placed at a depth of `2sqrt7cm` in water and a floating opaque disc is placed over the bulb so that the bulb is not visible from the surface. What is the minimum diameter of the disc?

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`R=(h)/(sqrt(mu^2-1))=(2sqrt7)/(sqrt((4/3)^2-1))`
`=(2sqrt7)/(sqrt7/3)=6cm`
Diameter of disc `=2R=12cm`
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CP SINGH-REFRACTION OF LIGHT BY PLANE SURFACES-Exercises
  1. A bulb is placed at a depth of 2sqrt7cm in water and a floating opaque...

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  2. When light moves from one medium to another (i) the frequency of lig...

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  3. (i) mu=(c)/(vm)=(vlambda)/(vlambdam) where c: speed of light in va...

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  4. Electromagnetic radiation of frequency n, wavelength lambda, travellin...

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  5. Absolute refractive indices of glass and water are 3//2 and 4//3. The ...

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  6. Light travels through a glass plate of thickness t and having refracti...

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  7. The refractive index of water, glass and diamond are 1.33, 1.50, 2.40 ...

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  8. A ray of light passes through four transparent media with refractive i...

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  9. A ray of light is incident at the glass-water interface at an angle I,...

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  10. If .imuj represnts the refractive index when a ray of light goes from ...

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  11. The bottom of a container filled with liquid appears slightly raised b...

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  12. A plane glass slab is placed over various coloured letters. The letter...

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  13. A transparent cube of 15 cm edge contains a small air bubble. Its appa...

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  14. A man standing in a swimming pool looks at a stone lying at the bottom...

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  15. A fish in water sees an object which is 24cm above the surface of wate...

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  16. A bird flies down vertically towards a water surface. To a fish inside...

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  17. A ball is dropped from a height of 20m above the surface of water in a...

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  18. A fish rising up vertically toward the surface of water with speed 3m...

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  19. P is a point on the axis of a concave mirror. The image of P, formed b...

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  20. A vessel of depth d is half filled with a liquid of refractive index m...

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  21. A plane mirror is placed at the bottom of a tank containing a liquid o...

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