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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.
पर्याय
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
| 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?
Where is the image when you look at something in a mirror?
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?
What type of reflection of light takes place from a cinema screen?
What is meant by 'reflection of light'?
The image formed by a plane mirror is :
(a) virtual, behind the mirror and enlarged.
(b) virtual, behind the mirror and of the same size as the object.
(c) real, at the surface of the mirror and enlarged.
(d) real, behind the mirror and of the same size as the object.
A ray of light strikes a plane mirror PQ at an angle of incidence of 30°, is reflected from the plane mirror and then strikes a second plane mirror QR placed at right angles to the first mirror. The angle of reflection at the second 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?
A ray of light passes from air into a block of glass. Does it bend towards the normal or away from it?
State whether the following statement is true or false:
Refraction occurs because light slows down in denser materials.
A ray of light travelling in air is incident on a rectangular glass block and emerges out into the air from the opposite face. Draw a labelled ray diagram to show the completer path of this ray of light. Mark the two points where the refraction of light takes place. What can you say about the final direction of ray of light?
Light travels more quickly through water than through glass.
- Which is optically denser: water or glass?
- If a ray of light passes from glass into water, which way will it bend: towards the normal or away from the normal?
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 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?
- What is the angle of refraction?
Water is optically denser than glass.
Light travels at a lower speed in water than in air.
Air is optically .......... than glass.
We can see the sun even when it is little below the horizon because of ______.
Choose and write the correct option.
If we gradually increase the angle of incidence of a ray of light passing through prism then …..
Define the principal focus of a concave mirror.
Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass? The speed of light in vacuum is 3 × 108 m s−1.
List four characteristics of the image formed by a concave lens of focal length 20 cm when the object is placed at a distance of 40 cm from its optical centre.
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.
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.
State whether true or false. If false, correct the statement.
The angle of deviation depends on the refractive index of the glass.
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
What is refractive index?
You are given water, mustard oil, glycerine and kerosene. In which of these media a ray of light incident obliquely at same angle would bend the most?
The angle of incidence for a ray of light having zero reflection angle is ______.
In the above diagram light is travelling through different media. It is noted by a scientist that ∠1= ∠3 = ∠4 but ∠2 < ∠1. Which of the following statement would be correct?
Which object use the reflection of light?
How does the light travel?
Assertion: The air bubble shines in water.
Reason: Air bubble shines due to the refraction of light.
Why a pencil partly immersed in water appears to be bent at the water surface.
Match the following:
| Column I | Column II | ||
| 1. | r > 90 | a. | Light gazes at the surface of separation between the two modes. |
| 2. | r = 90 | b. | No refraction. |
| 3. | r < 90 | c. | Refracted ray away from the normal |
