Advertisements
Advertisements
Question
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?
Advertisements
Solution
Man should walk 7.5 m towards the mirror.
The reason being, the image formed by a plane mirror is the same distance behind the mirror as it is between the object and the mirror. A distance of 5m between man and his image means that the distance between him and the mirror = `52`= 2.5 m.
Thus, the distance he should walk = 10 - 2.5 = 7.5 m.
APPEARS IN
RELATED QUESTIONS
Which property of light makes a pencil cast a shadow when it is held in front of a light source?
Fill in the following blank with a suitable word:
When light is reflected, the angles of incidence and reflection are ............ .
In which material do you think light rays travel faster-glass or air?
Why does a ray of light bend when it travels from one medium to another?
Name the phenomenon due to which a pencil partly immersed in water and held obliquely appears to be bent at the water surface.
State two factors on which the lateral displacement of the emergent ray depends.
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°
A vertical ray of light strikes the horizontal surface of some water:
What is the angle of incidence?
How does the light have to enter the glass:
for no refraction to happen?
Air is optically .......... than glass.
When a ray of light travels from water to air, it bends ............. the normal.
Match the Following
| Column A | Column B |
| (a) white Light | (1) Convex mirror |
| (b) Refraction | (2) Concave mirror |
| (c) Virtual images | (3) refraction |
| (d) Real images | (4) spectrum |
| (e) Prism | (5) ray of light from glass to air |
Draw suitable diagrams to illustrate how a beam of light incident parallel to the principal axis is reflected by:
(a) a concave mirror, and (b) a convex mirror
A light ray suffers reflection and refraction at the boundary in passing from air to water. Draw a neat labelled ray diagram to show it.
Define the principal focus of a concave mirror.
The size of image of an object by a convex lens of focal length 20 cm is observed to be reduced to `1/3` rd of its size . Find the distance of the object from the optical centre of the lens .
Write scientific reason.
The coin disappears in a vessel as it is seen from a specific location. But as soon as the water is poured into the vessel to a certain level, the coin appears.
The refractive index of four substances A, B, C, and D are 1.31, 1.43, 1.33, 2.4 respectively. The speed of light is maximum in
The bending of light as it passes from one medium to another is called ______.
A ray of light starting from diamond is incident on the interface separating diamond and water. Draw a labelled ray diagram to show. the refraction of light in this case.
