Previous Year Paper year:2019 : ICSE-X-Physics

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ICSE-X-Physics

Previous Year Paper year:2019

with Solutions - page 2

#1-e-ii
State one important factor which affects the critical angle of a given medium.

[2]

Ans : Nature of the two media in contact.

#2

#2-a
An electromagnetic radiation is used for photography in fog.

#2-a-i
Identify the radiation.
Ans : Infrared radiation

#2-a-ii
Why is this radiation mentioned by you, ideal for this purpose?

[2]

Ans : Because it can penetrate fog.

#2-b

#2-b-i
What is the relation between the refractive index of water with respect to air(_aμ_w) and the refractive index of air with respect to water (_wμ_a)
Ans :

#2-b-ii
If the refractive index of water with respect to air (_aμ_w) is ``\frac { 5 }{ 3 }``. Calculate the refractive index of air with respect to water (_wμ_a)

[2]

Ans : Given (_aμ_w) = ``\frac { 5 }{ 3 }``

Therefore, We have

#2-c
The specific heat capacity of a substance A is 3,800 J kg^-1K^-1 and that of a substance B is 400 J kg^-1K^-1. Which of the two substances is a good conductor of heat? Give a reason for your answer.

[2]

Ans : Substance B. Because it requires relatively little heat to raise its temperature.

#2-d
A man playing a flute is able to produce notes of different frequencies. If he closes the holes near his mouth, will the pitch of the note produced, increase or decrease? Give a reason.

[2]

Ans : The pitch will decrease, as the pitch is inversely proportional to the length of the vibrating air column.

#2-e
The diagram below shows a light source P embedded in a rectangular glass block ABCD of

critical angle 42°. Complete the path of the ray PQ till it emerges out of the block. [Write necessary angles.]

[2]

Ans : The path of ray is as shown:

#3

#3-a

#3-a-i
If the lens is placed in water instead of air, how does its focal length change?
Ans : Its focal length increases.

#3-a-ii
Which lens, thick or thin has greater focal length?
[2]
Ans : Thin lens.