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## Previous Year Papers

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Class 10 Class 12
Underline the correct alternative:
(c) The rate of change of total momentum of a many-particle system is proportional to the external force/sum of the internal forces on the system.

External force

Internal forces cannot produce any change in the total momentum of a body, irrespective of the direction. Hence, the total momentum of a many- particle system is proportional to the external forces acting on the system.
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What is watt?

SI unit of power is Watt.
773 Views

What are different units of energy?

The different units of energy are :

(i) Joule
(ii) Erg
(iii) eV
(iv) KWh
(v) Calorie.

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Is work a scalar or a vector quantity?

Work is dot product of two vectors. i.e. .

And dot product is a scalar quantity. Therefore, work is a scalar quantity.
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Define the unit joule.

Work done is said to be one joule if one newton of  force displaces the body through a distance of one meter in the direction of applied  force .
799 Views

Define watt.

Power is said to be one watt if one joule of work is done in one second.
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