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प्रश्न
Lights of different colours are used as signal for safety transport. From these, the wavelength of red light is _______ nm.
विकल्प
400
500
600
700
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उत्तर
Lights of different colours are used as signal for safety transport. From these, the wavelength of red light is 700 nm.
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संबंधित प्रश्न
Fill in the following blank with a suitable word:
When light is reflected, the angles of incidence and reflection are ............ .
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?
What is meant by 'reflection of light'?
Explain why, though both a plane mirror and a sheet of paper reflect light but we can see the image of our face in a plane mirror but not in a sheet of paper.
Write all the capital letters of the alphabet which look the same in a plane mirror.
The angle of reflection is equal to the angle of incidence:
(a) always
(b) sometimes
(c) under special conditions
(d) never
A ray of light travelling in glass emerges into air. State whether it will bend towards the normal or away from the normal.
A ray of light goes from water into air. Will it bend towards the normal or away from the normal?
State two effects caused by the refraction of light.
As light rays pass from water into glass, are they refracted towards the normal or away from the normal?
In which material do you think light rays travel faster-glass or air?
State whether the following statement is true or false:
Refraction occurs because light slows down in denser materials.
Why does a ray of light bend when it travels from one medium to another?
Fill in the following blank with suitable word:
Light travelling along a normal is ...............refracted.
When a light ray passes from air into glass, what happens to its speed? Draw a diagram to show which way the ray of light bends.
A coin in a glass tumbler appears to rise as the glass tumbler is slowly filled with water. Name the phenomenon responsible for this effect.
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?
Image is formed by a mirror due to refraction of light.
When a ray of light travels from air to glass, it bends .......... the normal.
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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.

State whether true or false. If false, correct the statement.
The angle of deviation depends on the refractive index of the glass.
Numerical problems.
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The refractive index of a transparent medium is always greater than ______.
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Noor, a young student, was trying to demonstrate some properties of light in her Science project work. She kept ‘X’ inside the box (as shown in the figure) and with the help of a laser pointer made light rays pass through the holes on one side of the box. She had a small butter-paper screen to see the spots of light being cast as they emerged.

Her friend noted the following observations from this demonstration:
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- Air is optically rarer than glass.
- Speed of light through a denser medium is faster than that of a rarer medium.
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Which one of the combinations of the above statements given below is correct.
A ray of light traveling in medium 1 strikes and travels into another transparent medium 2. If the speed of light is greater in medium 1, the ray will ______.
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