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A lens is placed between a souce of ligh...

A lens is placed between a souce of light and a wall.It forms images of areas `A_1` and `A_2` on the wall for its two different positions.The area of the source of light is

A

`sqrt(A_1A_2)`

B

`(A_1+A_2)/2`

C

`(A_1-A_2)/2`

D

`1/(A_1) + 1/(A_2)`.

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MODERN PUBLICATION-UNIT TEST -06-EXERCISE
  1. Focal length of a convex lens of refractive index 1.5 is 2 cm.Focal le...

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  2. A convex lens is dipped in a liquid,whose refrctive index is equal to ...

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  3. A lens is placed between a souce of light and a wall.It forms images o...

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  4. A boy is trying to start a fire by focussing sunlight on a piece of pa...

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  5. A bulb is located on a wll.Its image of equal size is to be obtained o...

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  6. A luminous object is placed at a distance of 30 cm from the convex len...

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  7. A lens having focal length f and aperture of diameter d//2 in the cent...

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  8. A plano-convex lens is made of a material of refrative index mu=1.5.Th...

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  9. The radius of curvatrure of a thin plano-convex lens is 10 cm (of cur...

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  10. A convex lens is dipped in a liquid,whose refrctive index is equal to ...

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  11. If a convex lens of focal length 80 cm and a concave lens of focal len...

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  12. A convex lens and a concave lens ,each having same focal length of 25 ...

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  13. Two thin lenses of focal length f1 and f2 are in contact and coaxial.T...

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  14. A beam of light composed of red and greeen ray is incident obliquely a...

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  15. A ray light is incident on a 60^@ prism at the minimum deviation posit...

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  16. The refracting angle of a prism is 60^@ nd the refractive index of the...

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  17. A ray is incident at an angle of incidence i on one surface of a prism...

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  18. The refractive index of the amterial of a prism is sqrt2 and its refra...

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  19. The focal length of a coverging lens is measured for violet,green and ...

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  20. If fv and fr are the focal lengths of a convex lens fro violet and red...

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