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प्रश्न
An optical device has been given to a student and he determines its focal length by focusing the image of the sun on a screen placed 24 cm from the device on the same side as the sun. Select the correct statement about the device.
(A) Convex mirror of focal length 12 cm
(B) Convex lens of focal length 24 cm
(C) Concave mirror of focal length 24 cm
(D) Convex lens of focal length 12 cm
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उत्तर
The optical device is a concave mirror because when light rays from a distant object (here it is Sun) fall on this mirror, its image is formed at the focus of the mirror on the same side as the object. Thus in the given case, distance between the mirror and the screen is the focal length of the concave mirror. Hence, the focal length of the given device (concave mirror) is 24 cm.
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संबंधित प्रश्न
Explain the following term related to spherical lenses:- principal axis
Image formed by a convex ______ is always virtual and smaller in size.
Which type of mirror can form a real image?
Which are the two convenient rays that are chosen to construct the image by a spherical mirror for a given object? Explain with the help of suitable ray diagrams.
State whether the image in part (a) is real or virtual?
The erect image formed by a concave mirror is of size double the size of object. How are u and v related?
An object 10 cm high is placed at a distance of 20 cm in front of a spherical mirror of focal length 25 cm. By scale drawing find the nature, position, and magnification of the image in the following case:
Concave mirror
