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प्रश्न
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उत्तर
Frequency of vibration of a stretched string can be increased by:
1. By increasing the tension in the string.
2. By decreasing the length of the string.
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संबंधित प्रश्न
If the speed of light in vacuum is 3 × 108 ms−1, find the speed of light in a medium of absolute refractive index 1.5.
A ray of light passes from water to air. How does the speed of light change?
Which colour of light travels fastest in any medium except air?
How is the reflection of light ray from a plane mirror different from the refraction of light ray as it enters a block of glass?
The refractive index of air with respect to glass is expressed as `""_g μ_a=sin i /sin r`.
- Write down a similar expression for aμg in terms of the angles i and r.
- If angle r = 90°, what is the corresponding angle i called?
- What is the physical significance of the angle i in part (b)?
After tracing the path of rays of light through a glass slab for three different angles of incidence, a student measured the corresponding values angle of refraction r and angle of emergence e and recorded them in the table given below:
|
S. No. |
∠i |
∠i |
∠e |
|
I |
30° |
20° |
31° |
|
II |
40° |
25° |
40° |
|
III |
50° |
31° |
49° |
The correct observations are:
(A) I and II
(B) II and III
(C) I and III
(D) I, II and III
What is the correct reason for blinking / flickering of stars? Explain it.
a) The blasts in the stars.
b) Absorption of star light by the atmosphere.
c) Motion of the stars.
d) Changing refractive index of gases in the atmosphere.
A fish swimming in a pond seems nearer than it really is. Explain.
State the relation between the refractive index μ and the velocity of light (vm) in that medium.
Comment on the statement ‘The refractive index of glass is 3/2.’
