Advertisements
Advertisements
प्रश्न
State two uses of a concave mirror.
Advertisements
उत्तर
Two uses of concave mirror are :
- Concave mirror is used as REFLECTOR in headlights of cars and in searchlight. The source of light (bulb) is placed at the principal focus and the reflector forms a parallel beam of light.
- For doctors to examine throat, ear, nose and eyes, light is focused with the help of a concave mirror.
APPEARS IN
संबंधित प्रश्न
Draw a ray diagram to show the path of the reflected ray corresponding to an incident ray of light parallel to the principal axis of a convex mirror and show the angle of incidence and angle of reflection on it.
Draw ray diagrams to show the principal focus of a concave mirror.
List four characteristics of the images formed by plane mirrors.
Draw diagram to represent the action of a concave mirror on a beam of parallel light rays. Mark on this diagram principal axis, focus F, centre of curvature C, pole P and focal length f, of the concave mirror.
Make labelled ray diagrams to illustrate the formation of:
a virtual image by a converging mirror.
Mark clearly the pole, focus, centre of curvature and position of object in each case.
A large concave mirror has a radius of curvature of 1.5 m. A person stands 10 m in front of the mirror. Where is the person's image?
A _____________ mirror is used by a dentist.
Rays from Sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that size of its image is equal to the size of the object?
In the headlights of motor vehicles, ______ mirrors are used as reflectors.
A student took three concave mirrors of different focal lengths and performed the experiment to see the image formation by placing an object at different distance with these mirrors as shown in the following table.
| Case No. | Object-distance | Focal length |
| I | 45 cm | 20 cm |
| II | 30 cm | 15 cm |
| III | 20 cm | 30 cm |
Now answer the following questions:
(a) List two properties of the image formed in Case I.
(b) In which one of the cases given in the table, the mirror will form real image of same size and why?
(c) Name the type of mirror used by dentists. Given reason why do they use such type of mirrors.
OR
(c) Look at the table and identify the situation (object distance and focal length) which resembles the situation in which concave mirrors are used as shaving mirrors? Draw a ray diagram to show the image formation in this case.
