Previous Year Paper year:2009 : ICSE-X-Physics

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ICSE-X-Physics

Previous Year Paper year:2009

with Solutions - page 2

#2-a [2]
A ray of light strikes the surface of a rectangular glass block
such that the angle of incidence is (i) 0°l (ii) 42°. Sketch a
diagram to show the approximate path taken by the ray in each
case as it passes through the glass block and emerges from it.
Ans : (i.) Given : i = 0°, ∴ r = 0.

(ii.) Given : i = 42°, ∴ e = 42°.

#2-b [2]
State the conditions required for total internal reflection of light
to take place.
Ans : (i.) Light must go from a denser to a rarer medium.
(ii.) The angle of incidence must be more than the critical angle.

#2-c [2]
Copy and complete the following table:

Types of Lens Position of Object Nature of Image Size of Image
Convex At F
Concave At infinity
Ans :

Type of lens Position of Object Nature of Image Size of Image

Convex At F Real and inverted Highly magnified

Concave At infinity Virtual and erect Highly Diminished

#2-d [2]

#2-d-i
Why is white light considered to be polychromatic in
nature?
Ans : Because it contains number of wave lengths (4000 Å-8000 Å) and there are seven colours in it (VIBGYOR).

#2-d-ii
Give the range of the wavelength of those electromagnetic
waves which are visible to us.
Ans : 4000 Å-8000 Å.

#2-e [2]
An ultrasonic wave is sent from a ship towards the bottom of
the sea. It is found that the time interval between the sending
and the receiving of the wave is 1.5 seconds. Calculate the
depth of the sea if the the velocity of sound in sea water is
1400 ms-1.
Ans :

#3

#3-a [2]
A stringed musical instrument, such as the Sitar, is provided
with a number of wires of different thicknesses. Explain the
reason for this.
Ans : Let

So the frequency of sound depend on the thickness or radius of the wire there-fore in stringed musical instrument different thickness wires give different frequency sound.

#3-b [2]
What is meant by noise pollution? Write the name of one source
of sound that causes noise pollution.
Ans : It is produced by an irregular succession of disturbances. It is harsh, discordant and displeasing to the ear. This sound level is 120 dB above. Main source of noise pollution are sound of vehicles and DJ's.

#3-c [2]
The equivalent resistance of the following circuit diagram is 4. .
Calculate the value of x.

Ans : Between the points A and B, total resistance of one arm is R₁ (5 + x) and total resistance of other arm is R₂ (8 + 4). Now equivalent resistance (R) between A and B is :

#3-d [2]
An electric heater is rated 1000W.200V. Calculate:
Ans : Given : P = 1000 W, V = 200 V,

#3-d-i
the resistance of the heating element.

#3-d-ii
the current flowing through it.

#3-e [2]

Ans : (i) The properties of the copper wire :
(1) It is a good conductor of electricity.
(2) It is of low resistivity and high melting point.