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प्रश्न
Explain how the formation of a rainbow occurs.
उत्तर
- The beautiful phenomenon of the rainbow is a combination of different phenomena – dispersion, refraction, and reflection of light.
- The rainbow appears in the sky after a rain shower.
- The water droplets act as small prisms.
- When sunlight enters the water droplets present in the atmosphere, they refract and disperse the incident sunlight.
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Then they reflect it internally inside the droplet and finally again refract it.
- As a collective effect of all these phenomena, the seven coloured rainbows are observed.
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संबंधित प्रश्न
What is refraction of light?
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'?
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.
The image in a plane mirror is virtual and laterally inverted. What does this statement mean?
The image of an object formed by a plane mirror is:
(a) virtual
(b) real
(c) diminished
(d) upside-down
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?
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 ______.
If a ray of light goes from a rarer medium to a denser medium, will it bend towards the normal or away from it?
As light rays pass from water into glass, are they refracted towards the normal or away from the normal?
Fill in the following blank with suitable word:
Light travelling along a normal is ...............refracted.
What is meant by 'refraction of light'? Draw a labelled ray diagram to show the refraction of light.
Light travels more quickly through water than through glass.
Which is optically denser : water or glass?
Light travels more quickly through water than through glass.
If a ray of light passes from glass into water, which way will it bend : towards the normal or away from the normal?
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.
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°
How does the light have to enter the glass:
for no refraction to happen?
A ray of light when passes from glass to air, bends towards the normal.
The depth of a pond when seen from above appears to be less.
When a ray of light travels from air to glass, it bends .......... the normal.
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
Choose and write the correct option.
If we gradually increase the angle of incidence of a ray of light passing through prism then …..
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The speed of light varies in different media.
Write scientific reason.
The sun appears on the western horizon for some time after sunset.
Write scientific reason.
The bottom of a pond appears raised.
Observe the given figure and write appropriate phenomenon of light in the box.
Explain the working of a periscope.
State whether true or false. If false, correct the statement.
The angle of deviation depends on the refractive index of the glass.
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.
What is refractive index?
Which object use the reflection of light?
A star appears twinkling into the sky because of the reflection of light by the atmosphere.
Twinkling of stars and Mirage are the two phenomena occurring due to refraction.
Why a pencil partly immersed in water appears to be bent at the water surface.
How do twinkling stars occur? (or) what is the cause of the twinkling of stars?
