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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
Explain the following term related to spherical lenses:- centres of curvature
Match the items given in Column I with one or more items of Column II.
| Column I | Column II | ||
| (a) | A plane mirror | (i) | Used as a magnifying glass. |
| (b) | A convex mirror | (ii) | Can form image of objects spread over a large area. |
| (c) | A convex lens | (iii) | Used by dentists to see enlarged image of teeth. |
| (d) | A concave mirror | (iv) | The image is always inverted and magnified. |
| (e) | A concave lens | (v) | The image is erect and of the same size as the object. |
| (vi) | The image is erect and smaller in size than the object. |
The letter F is placed in front of a plane mirror:
What is the name of the phenomenon involved?
Name the two types of spherical mirrors. What type of mirror is represented by the:
- back side of a shining steel spoon?
- front side of a shining steel spoon?
Complete the following sentence:
All the distances are measured from the .......... of a spherical mirror.
State the two kinds of spherical mirror and distinguish them with the aid of proper diagrams.
Define the terms pole, principal axis and centre of curvature with reference to a spherical mirror.
Define the terms focus and focal length of a concave mirror. Draw diagram to illustrate your answer.
Does the mirror mentioned in part (b) form real image for all locations of the object?
Draw a ray diagram to show the formation of image of an object kept in front of a convex mirror. State three characteristics of the image.
A concave mirror forms a real image of an object placed in front of it at a distance 30 cm, of size three times the size of object. Find
- the focal length of mirror
- position of image.
Select the correct option:
A mirror forms a virtual image (diminished) of an object, whatever be the position of object:
Define the following term:
convex mirror
Define the following term in relation to concave mirror.
Principal axis
Define the following term in relation to concave mirror.
Principal focus
What is the relationship between the focal length and radius of curvature?
Define the term Centre of curvature.
If the focal length of a spherical mirror is 10 cm, what is the value of its radius of curvature?
Define focal length.
If the real image of a candle flame formed by a lens is three times the size of the flame and the distance between lens and image is 80 cm, at what distance should the candle be placed from the lens?
What is the difference between virtual images of an object formed by a concave mirror and a convex mirror?
The image formed in a plane mirror is always inverted.
