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If a convex lens of focal length 80 cm a...

If a convex lens of focal length 80 cm and a concave lens of focal length 50 cm re combined together ,what will be their resulting power?

A

`+6.5 D`

B

`-6.5 D`

C

`+7.5D`

D

`-0.75D`.

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MODERN PUBLICATION-UNIT TEST -06-EXERCISE
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  2. A convex lens is dipped in a liquid,whose refrctive index is equal to ...

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

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

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

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

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

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

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

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

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

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

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  13. Rainbow is formed due to combination fo

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  14. For relaxed eye,magnifying power of a microscope is

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  15. An astronomical telescope of ten fold angular magnification has a leng...

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  16. Which one off the following phenomena is not explained by Huygens' con...

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  17. Ratio of intensity of two waves is given by 4:1. Then, ratio of the am...

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  18. How is interference pattern in double slit exp[eriment affected,if a s...

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  19. Interference was observed in interference chamber,when air was present...

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  20. In Young's double silt experiment, the fringe width obtained is 3 mm i...

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