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प्रश्न
In torches, search lights and headlights of vehicles the bulb is placed ______.
विकल्प
between the pole and the focus of the reflector
very near to the focus of the reflector
between the focus and centre of curvature of the reflector
at the centre of curvature of the reflector
उत्तर
In torches, search lights and headlights of vehicles the bulb is placed very near to the focus of the reflector.
Explanation -
In torches, search lights and headlights of vehicles concave mirrors are used. When a light source is placed at the focus of the mirror, after reflection light rays become parallel to the principal axis. Due to this, the bulb is placed very near to the focus of the reflector.
संबंधित प्रश्न
A 4 cm tall object is placed on the principal axis of a convex lens. The distance of the object from the optical centre of the lens is 12 cm and its sharp image is formed at a distance of 24 cm from it on a screen on the other side of the lens. If the object is now moved a little away from the lens, in which way (towards the lens or away from the lens) will he have to move the screen to get a sharp image of the object on it again? How will the magnification of the image be affected?
Define the following term in the context of spherical mirrors:- Principal axis
We can obtain an enlarged and erect image by a convex mirror.
Write true or false
A virtual image formed by a spherical mirror is always erect and situated behind the mirror.
The diagram below in Figure, shows a convex mirror. C is its centre of curvature and F is its focus. (i) Draw two rays from A and hence locate the position of image of object OA. Label the image IB. (ii) State three characteristics of the image.
Discuss the position and nature of image formed by a concave mirror when an object is moved from infinity towards the pole of mirror.
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).
Answer the following question.
Write the modification in the curvature of the eye lens which enables us to see the nearby objects clearly?
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:
Convex mirror
