Advertisements
Advertisements
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.
Advertisements
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.
APPEARS IN
संबंधित प्रश्न
What is refraction of light?
What is lateral inversion? Explain by giving a suitable example.
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?
What is meant by 'reflection of light'?
A man sits in an optician's chair looking into plane mirror which is 2 m away from him and views the image of a chart which faces the mirror and is 50 cm behind his head. How far away from his eyes does the chart appear to be?
A ray of light goes from water into air. Will it bend towards the normal or away from the normal?
Name the phenomenon due to which a swimming pool appears less deep than it really is.
With the help of a labelled diagram, explain why a tank full of water appears less deep than it actually is.
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?
How does the light have to enter the glass:
for no refraction to happen?
Draw a diagram showing the refraction of a light ray from water to glass. Label on it the incident ray, the angle of incidence (/), and the angle of refraction (r)
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.
Explain with diagrams how refraction of incident light takes place from
- rarer to denser medium
- denser to rarer medium
- normal to the surface separating the two media.
What is refractive index?
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?
A star appears twinkling into the sky because of the reflection of light by the atmosphere.
