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प्रश्न
Which one of the following materials cannot be used to make a lens?
विकल्प
Water
Glass
Plastic
Clay
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उत्तर
Clay
Explanation:
since it is opaque and does not let light pass through it.
संबंधित प्रश्न
State the power of a lens S.I. unit.
What is the focal length of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm? Is the system a converging or a diverging lens? Ignore thickness of the lenses.
What can you see in a completely dark room? If you switch on an electric bulb in this dark room as a light source, explain how you could now see:
(a) the electric bulb
(b) a piece of white paper
Define the term focal length of a lens.
How is the power of a lens related to its focal length?
The power of a lens is + 1.0 D is :
A convex lens is of focal length 20 cm. Find its power.
If the lens is of focal length 25 cm. Calculate the power of the lens.
The power of the magnifying glass depends on the distance of the magnifying glass from object.
The focal length of a double convex lens is equal to the radius of curvature of either surface. What is the refractive index of its material?
