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प्रश्न
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.
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उत्तर
In the above figure, the portion BO of the pencil AO is immersed in water and it appears to be bent at point B. The light ray OC coming from the lower end O of the pencil passes from water to air and gets refracted away from the normal in the direction CX. Another ray OD is refracted in the direction DY. These two refracted rays, CX and DY, meet at point I, when they are produced backwards. Point I is nearer to the water surface than point O. Therefore, a virtual image of end O of the pencil is formed as point I.
So, human eye at position E sees the end O at point I; i.e., pencil appears to be bent.
If water is replaced by another liquid, which is optically denser than water, the bending of pencil will increase because an optically denser medium causes more refraction or more bending of light rays.
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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 |
What are the important differences between looking at a photograph of your face and looking at yourself in a plane mirror?
What type of reflection of light takes place from a cinema screen?
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 of an object formed by a plane mirror is:
(a) virtual
(b) real
(c) diminished
(d) upside-down
The figure given alongside shows the image of a clock as seen a plane mirror. The correct time is:
Figure
(a) 2.25
(b) 2.35
(c) 6.45
(d) 9.25
A ray of light goes from water into air. Will it bend towards the normal or away from the normal?
Which phenomenon of light makes the water to appear shallower than it really is?
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?
Match the Following
| Column A | Column B |
| (a) white Light | (1) Convex mirror |
| (b) Refraction | (2) Concave mirror |
| (c) Virtual images | (3) refraction |
| (d) Real images | (4) spectrum |
| (e) Prism | (5) ray of light from glass to 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
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?
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.
Lights of different colours are used as signal for safety transport. From these, the wavelength of red light is _______ nm.
State whether true or false. If false, correct the statement.
The angle of deviation depends on the refractive index of the glass.
Light bends as it passes from one medium to another. What is this phenomenon called?
A water tank appears shallower when it is viewed from the top due to refraction.
Twinkling of stars and Mirage are the two phenomena occurring due to refraction.
