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प्रश्न
A student focused the Sun rays using an optical device 'X' on a screen S as shown.
From this it may be concluded that the device 'X' is a (select the correct option)
(A) Convex lens of focal length 10 cm.
(B) Convex lens of radius of curvature 20 cm.
(C) Convex lens of focal length 20 cm.
(D) Concave mirror of focal length 20 cm.
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उत्तर
Light rays from infinity are converged at the focal point of the convex lens. Therefore, the focal length of the convex lens is 20 cm.
Hence, the correct option is C.
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संबंधित प्रश्न
Write two more characteristics of the image.
Select the correct option:
Looking into a mirror one finds her image diminished, the mirror is:
Define the following term:
convex mirror
Define the following term in relation to concave mirror.
Center of curvature
Define the following term in relation to concave mirror.
Focal length
Define the following term in relation to concave mirror.
Aperture
The radius of curvature of a spherical mirror is 18 cm. What is the focal length of this mirror?
A spherical mirror whose reflecting surface is curved outwards is called ______ mirror.
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