Previous Year Paper year:2018 : ICSE-X-Physics

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ICSE-X-Physics

Previous Year Paper year:2018

with Solutions -

#
ICSE Board
Class X Physics
SCIENCE Paper - I
Board Paper - 2018
Time: 2 hours Maximum Marks: 80
General Instructions:
Answers to this paper must be written on the paper provided separately.
You will not be allowed to write during the first 15 minutes.
This time is to be spent in reading the question paper.
The time given at the head of paper is the time allotted for writing the answers.
Section I is compulsory. Attend any four questions from Section II.
The intended marks of questions or parts of questions are given in brackets [ ].

# [40]
Section : I
Attempt all questions from this section.

#1

#1-a [2]

#1-a-i
State and define the SI unit of power.
Ans : The SI unit of power is ``\pu{watt}``. It is denoted by the symbol ``\pu{W}``.

#1-a-ii
How is the unit hose power related to the S.I. unit of power?
Ans : ``\pu{1 horsepower = 746 watt}``

#1-b [2]
State the energy changes in the following cases while in use:

#1-b-i
An electric iron.
Ans : In electric iron ,Electrical energy is converted to heat energy.

#1-b-ii
A ceiling fan.
Ans : In ceiling fan, Electrical energy is converted to mechanical energy.

#1-c [2]
The diagram below shows a lever in use:

#1-c-i
To which class of levers does it belong?
Ans : As the load is in between the effort and the fulcrum. So, this is a class II
lever.

#1-c-ii
Without changing the dimensions of the lever, if the load is shifted
towards the fulcrum what happens to the mechanical advantage of the
lever?
Ans : If the load arm is shifted towards the fulcrum, the length of the load arm
decreases.
As MA(Mechanical advantage) is equal to the ratio of the length of the
effort arm to the length of the load arm. Hence, mechanical advantage
increases.

#1-d [2]

#1-d-i
Why is the ratio of the velocities of light of wavelengths 4000 ``\dot A ``
and 8000 ``\dot A `` in vacuum 1:1?
Ans : As both light of given wavelengths are electromagnetic waves and electromagnetic waves travel at the same speed in vacuum irrespective of its wavelength, hence the ratio is 1:1.

#1-d-ii
Which of the above wavelengths has a higher frequency?
Ans : Speed is the product of frequency and wavelength.
``V = f \lambda``
Since speed is constant, light of lower wavelength 4000 ``\dot A `` will have higher frequency.