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प्रश्न
A student obtained on a screen the sharp image of a candle flame placed at the farther end of laboratory table using a concave mirror. For getting better value of focal length of the mirror, the teacher suggested to him to focus the sun. What should the student do?
(A) Should move the mirror away from the screen.
(B) Should move the mirror towards the screen.
(C) Should move the mirror and screen both towards the sun.
(D) Should move only the screen towards the sun.
उत्तर
Initially, the screen was placed beyond the focus to capture the image of the candle flame placed at a finite distance from the mirror. So, in order to capture a bright image of the Sun (at infinity) on the screen, the student should move the mirror towards the screen.
Hence, the correct option is B.
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संबंधित प्रश्न
Define the following term in the context of spherical mirrors:- Principal axis
Which type of mirror can form a real image?
The diverging lens in part (a) is replaced by a converging lens also of focal length 100 mm. The object remains in the same position and an image is formed by the converging lens. Compare two properties of this image with those of the image formed by the diverging lens in part (a).
A concave lens produces an image 20 cm from the lens of an object placed 30 cm from the lens. The focal length of the lens is:
(a) 50 cm
(b) 40 cm
(c) 60 cm
(d) 30 cm
State the kind of mirror used
(a) by a dentist, and
(b) as a street light reflector.
Name the kind of mirror used to obtain:
A virtual and enlarged image
Draw a ray diagram in each of the following cases to show the formation of image, when the object is placed :
(i) between the optical centre and principal focus of a convex lens.
(ii) anywhere in front of a concave lens.
(iii) at 2F of a convex lens.
State the signs and values of magnifications in the above-mentioned cases (i) and (ii).
Define the following term in relation to concave mirror.
Center of curvature
Define the following term in relation to concave mirror.
Aperture
What is the focal length (f) of a mirror?
