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प्रश्न
State two uses of a concave mirror.
Give the uses of a concave mirror.
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उत्तर १
Two uses of concave mirror:
(i) It is used as a shaving mirror.
(ii) It is used as reflector in torch, head light of automobiles etc.
उत्तर २
The uses of a concave mirror are
(i) In torches and headlights: The source of light is placed at the focus to obtain a parallel beam of light.
(ii) In floodlights: The source of light is placed just beyond the center of curvature so as to get an intense beam of light.
(iii) Reflecting mirrors for projector lamps: The object is placed at the center of curvature to obtain an image of the same size.
- To collect heat radiations in solar devices: Heat radiations from the sum coming from infinity are brought to focus by a concave mirror in its focal plane.
- Shaving mirror, dentist’s mirror: It produces an erect virtual and highly magnified image of an object placed between its pole and focus.
vi. Solar furnaces: Large concave mirrors are used to concentrate sunlight to produce heat in a solar furnace.
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संबंधित प्रश्न
Explain the following term related to spherical lenses:- optical centre
Define the following term in the context of spherical mirrors:- Principal focus
Explain the following term related to spherical lenses:- principal focus
Image formed by a convex ______ is always virtual and smaller in size.
We can obtain a real, enlarged and inverted image by a concave mirror.
Which type of mirror can form a real image?
What kind of mirror is required for obtaining a virtual image of the same size as the object?
Name the two types of spherical mirrors. What type of mirror is represented by the:
front side of a shining steel spoon?
When a spherical mirror is held towards the sun and its sharp image is formed on a piece of a carbon paper for some time, a hole is burnt in the carbon paper.
What is the advantage of using a carbon paper rather than a white paper?
Name the spherical mirror which can produce a virtual and diminished image of an object.
A student obtained a sharp image of a burning candle, placed at the farther end of a laboratory table, on a screen using a concave mirror. For getting better value of focal length of the mirror, the subject teacher suggested him for focusing a well illuminated distant object. What should the student do?
(A) He should move the mirror away from the screen.
(B) He should move the mirror slightly towards the screen.
(C) He should move the mirror as well as the screen towards the newly selected object.
(D) He should move only the screen towards the newly selected object.
If a spherical mirror breaks, what type of mirrors are the individual pieces?
Name the two kinds of spherical mirrors and distinguish between them.
How is the focal length of a spherical mirror related to its radius of curvature?
An object 5 cm high is placed at a distance 60 cm in front of a concave mirror of focal length 10 cm. Find the position and size of the image.
Define the following term in relation to concave mirror.
Principal axis
Define the following term in relation to concave mirror.
Principal focus
Define the term principal focus in case of convex mirror. Draw a convex mirror and show its principal focus and focal length clearly.
In the following figure shows a concave mirror with its pole (P), focus (F) and centre of curvature (C). Draw a ray diagram to show the formation of the image of an object AB by the concave mirror.
Complete the following diagrams shown in the below figure by drawing the reflected ray for each incident ray.
Numerical problem.
The radius of curvature of a spherical mirror is 25 cm. Find its focal length.
A spherical mirror whose reflecting surface is curved outwards is called ______ mirror.
A converging lens of focal length f is placed at a distance 0.3 m from an object to produce an image on a screen 0.9 m from the lens. With the object and the screen in the same positions, an image of the object could also be produced on the screen by placing a converging lens of focal length.
Define the following terms in the context of a diverging mirror:
- Principal focus
- Focal length
Draw a labelled ray diagram to illustrate your answer.
