Advertisements
Advertisements
प्रश्न
With the help of a labelled ray-diagram, describe how a plane mirror forms an image of a point source of light placed in front of it. State the characteristics of the image formed in a plane mirror.
Advertisements
उत्तर
Consider a small object (a point source of light), placed in front of a plane mirror MM' (figure 1). The mirror will form an image I of the object O. This process of image formation is explained as follows:
The object O gives out light rays in all directions. Now, a ray of light OA, coming from the object O, is incident on the plane mirror at point A. OA gets reflected in the direction AX in accordance with the law of reflection, which states that the angle of reflection r1 equals the angle of incidence i1. Another ray of light OB, coming from the object O, strikes the mirror at point B. OB gets reflected in the direction BY, thus, making the angle of reflection r2 equal to the angle of incidence i2.
The two reflected rays AX and BY are divergent and cannot meet on the left side. Let's produce the reflected rays AX and BY backwards. They meet at a point I behind the mirror. When the reflected rays AX and BY enter the eye of a person at position E, the eye sees the rays in the direction in which they enter. So, the person looking into the mirror from position E sees the reflected rays as if they are coming from the point I behind the mirror. Thus, the point I is the image of the object O formed by the plane mirror.
The image produced by the plane mirror is virtual, laterally inverse and of the same size as the object.
APPEARS IN
संबंधित प्रश्न
| Column I | Column II | Column III | |
| 1 | Dispersion | Long-sightedness | Twinkling of stars |
| 2 | Refraction | Splitting of white light into component colours | Convex lens |
| 3 | Hypermetropia | Change in the direction of the ray of light due to change in medium | Spectrum of seven colours |
If an object is placed at a distance of 10 cm in from of a plane mirror, how far would it be from its image?
A ray of light strikes a plane mirror such that its angle of incidence is 30°. What angle does the reflected ray make with the mirror surface?
Write the word AMBULANCE as it would appear when reflected in a plane mirror. Why is it sometimes written in this way (as its mirror image) on the front of an ambulance?
State the uses of plane mirrors.
The image in a plane mirror is virtual and laterally inverted. What does this statement mean?
The angle of reflection is equal to the angle of incidence:
(a) always
(b) sometimes
(c) under special conditions
(d) never
A man stands 10 m in front of a large plane mirror. How far must the walk before he is 5 m away from his image?
When a ray of light passes from air into glass, is the angle of refraction greater than or less than the angle of incidence?
In which material do you think light rays travel faster-glass or air?
Show the lateral displacement of the ray on the diagram.
Light travelling from a denser medium to a rarer medium along a normal to the boundary:
(a) is refracted towards the normal
(b) is refracted away from the normal
(c) goes along the boundary
(d) is not refracted
A ray of light passes from a medium X to another medium Y. No refraction of light occurs if the ray of light hits the boundary of medium Y at an angle of:
(a) 0°
(b) 45°
(c) 90°
(d) 120°
When a ray of light travels from water to air, it bends ............. the normal.
A small air bubble in a glass block when seen from above appears to be raised because of ______.
List in proper sequence the steps of the experiment for determining the approximate focal length of a given concave mirror by obtaining the image of a distant object.
The laws of reflection hold true for ______.
Lights of different colours are used as signal for safety transport. From these, the wavelength of red light is _______ nm.
The incident rays and refracting rays are on opposite sides of the normal.
Which is optically denser out of the two medium M1& M2 having the refractive indices = 1.71 and 1.36 respectively?
