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An image formed on a screen is three tim...

An image formed on a screen is three times the size of the object. The object and screen are 80 cm apart when the image is sharply focused.
a) State which type of lens is used.
b) Calculate focal length of the lens.

Text Solution

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a) Convex lens
b) `+15` cm
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LAKHMIR SINGH & MANJIT KAUR-REFRACTION OF LIGHT-Exercise
  1. The magnification produced by a spherical lens and a spherical mirror ...

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  2. An object is 2m from a lens which forms an erect image one-fourth (exa...

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  3. An image formed on a screen is three times the size of the object. The...

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  4. The lens A has a focal length of 25 cm whereas another lens B has a fo...

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  5. Which causes more bending (or more refraction) of light rays passing t...

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  6. Name the physical quantity whose limit unit is dioptre.

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  7. Define one dioptre of power of a lens.

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  8. Which type of lens has a) a positive power, and b) a negative power?

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  9. Which of the two has a greater power, a lens of short length or a lens...

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  10. How is the power of a lens related to its focal length?

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  11. Which has more power, a thick concave lens or a thin convex lens, made...

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  12. The focal length of a convex lens is 25 cm. What is its power?

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  13. What is the power of a convex lens of focal length 0.5 m?

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  14. A converging lens has a focal length of 50mm. What is the power of the...

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  15. What is the power of a convex lens whose focal length is 80 cm?

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  16. The power of a lens is +0.2D. Calculate its focal length.

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  17. The power of lens is, -2D. Calculate its focal length.

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  18. The optician's prescription for a spectacle lens is marked +0.5D. What...

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  19. What is the nature of a lens whose power of -4 D ?

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  20. The optician's prescription for a spectacle lens is marked +0.5D. What...

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