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Question
Lights of different colours are used as signal for safety transport. From these, the wavelength of red light is _______ nm.
Options
400
500
600
700
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Solution
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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Where is the image when you look at something in a mirror?
What type of reflection of light takes place from a cinema screen?
The boy walks towards the mirror at a speed of 1 m/s. At what speed does his image approach him?
An extended object in the form of an arrow pointing upward has been placed in front of a plane mirror. Draw a labelled ray-diagram to show the formation of its image.
Define the following terms used in the study of reflection of light by drawing a labelled ray-diagram:
- Incident ray
- Point of incidence
- Normal
- Reflected ray
- Angle of incidence
- Angle of reflection
The image of an object formed by a plane mirror is:
(a) virtual
(b) real
(c) diminished
(d) upside-down
If a ray of light goes from a rarer medium to a denser medium, will 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.
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.
- With the help of a diagram, show how when light falls obliquely on the side of a rectangular glass slab, the emergent ray is parallel to the incident ray.
- Show the lateral displacement of the ray on the diagram.
Show the lateral displacement of the ray on the diagram.
Explain with the help of a labelled ray diagram, why a pencil partly immersed in water appears to be bent at the water surface. State whether the bending of pencil will increase or decrease if water is replaced by another liquid which is optically more dense than water. Give reason for your answer.
A vertical ray of light strikes the horizontal surface of some water:
- What is the angle of incidence?
- What is the angle of refraction?
A vertical ray of light strikes the horizontal surface of some water:
What is the angle of refraction?
Light travels at a lower speed in water than in air.
Water is optically .......... than air.
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
A ray of light passes from medium 1 to medium 2. Which of the following quantities of the refracted ray will differ from that of the incident ray: Speed, intensity, frequency, wavelength?
Fill in the blank and Explain the completed sentences.
The change in ______ of light rays while going from one medium to another is called refraction.
What is atmospheric reflection? Explain with the help of a labelled diagram that the position of a star as seen by us is not its true position.
Light changes its direction when going from one transparent medium to another transparent medium. This is called _______.
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.
Write scientific reason.
A pencil appears to be broken near the surface of water.
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 ______.
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:
- Glass is optically rarer than air.
- Air and glass allow light to pass through them with the same velocity.
- Air is optically rarer than glass.
- Speed of light through a denser medium is faster than that of a rarer medium.
- The ratio: sin of angle of incidence in the first medium to the ratio of sin of angle of refraction in the second medium, gives the refractive index of the second material with respect to the first one.
Which one of the combinations of the above statements given below is correct.
The phenomenon of light passing through the object is called ______.
Light bends as it passes from one medium to another. What is this phenomenon called?
Light is refracted or bent while going from one medium to another because of its ______ changes.
Mirage is an example of refraction and the total internal reflection of light.
In refraction of light through a glass slab, the directions of the incident ray and the refracted ray are ______.
When a ray of light travels normal to the given surface, then the angle of refraction is ______.
