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प्रश्न
State whether the following statement is true or false:
Refraction occurs because light slows down in denser materials.
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उत्तर
True.
The refraction of light is due to the change in the speed of light on going from one medium to other. The speed of light ray slows down in denser materials.
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संबंधित प्रश्न
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?
A wall reflects light and a mirror also reflects light. What difference is three in the way they reflect light?
Define the following terms used in the study of reflection of light by drawing a labelled ray-diagram:
(a) Incident ray
(b) Point of incidence
(c) Normal
(d) Reflected ray
(e) Angle of incidence
(f) Angle of reflection
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.
An object is placed 20 cm in front of a plane mirror. The mirror is moved 2 cm towards the object. The distance between the positions of the positions of the original and final images seen in the mirror is ______.
When a ray of light travelling in glass enters into water obliquely:
(a) it is refracted towards the normal
(b) it is not refracted at all
(c) it goes along the normal
(d) it is refracted away from the normal
A vertical ray of light strikes the horizontal surface of some water:
What is the angle of incidence?
Light travels at a lower speed in water than in 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
We can see the sun even when it is little below the horizon because of ______.
The phenomenon of change in the direction of light when it passes from one transparent medium to another is called ___________.
Due to _______ pencil looks bent in water, in the given experiment.
Lights of different colours are used as signal for safety transport. From these, the wavelength of red light is _______ nm.
Observe the given figure and name the following.
| Ray AB | |
| Ray NM | |
| Ray MD | |
| ∠ r |
Numerical problems.
The speed of light in water is 2.25 × 108 ms–1. If the speed of light in vacuum is 3 × 108 ms–1, calculate the refractive index of water.
A pencil when dipped in water in a glass tumbler appears to be bent at the interface of air and water. Will the pencil appear to be bent to the same extent, if instead of water we use liquids like, kerosene or turpentine. Support your answer with reason.
When light passes from one medium to another the ray gets bent. This property of light is called ______.
Twinkling of stars and Mirage are the two phenomena occurring due to refraction.
Assertion: The air bubble shines in water.
Reason: Air bubble shines due to the refraction of light.
How do twinkling stars occur? (or) what is the cause of the twinkling of stars?
