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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
Name the spherical mirror which can produce a virtual and diminished image of an object.
Three mirrors are created from a single sphere. Which of the following - pole, centre of curvature, radius of curvature, principal axis - will be common to them and which will not be common?
Explain the following term:
Incident ray
Draw diagram/diagrams to show them.
Discuss the position and nature of image formed by a concave mirror when an object is moved from infinity towards the pole of mirror.
The erect image formed by a concave mirror is of size double the size of object. How are u and v related?
Define the following term in relation to concave mirror.
Focal length
Define the term principal focus in case of convex mirror. Draw a convex mirror and show its principal focus and focal length clearly.
Name the type of mirror used in the following situation:
Side/rear-view mirror of a vehicle
Support your answer with reason.
What is the focal length (f) of a mirror?
