Tag: energy and its forms

Questions Related to energy and its forms

The internal energy change when a system goes from state A to B is $40$ kJ/mole. If the system goes from A to B by a reversible path and returns to state A by an irreversible path what would be the net change in internal energy?

physics energy and its forms idea of energy introduction to work and energy work and energy

  1. $40$ kJ

  2. $> 40$ kJ

  3. $< 40$ kJ

  4. Zero

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Correct Option: D
Explanation:
For a cyclic process the net change in the internal energy is zero because the change in internal energy doesnot depend on the path.

Which of the following can be negative 

physics energy and its forms idea of energy introduction to work and energy work and energy

  1. Kinetic energy

  2. Potential energy

  3. Mechanical energy

  4. All of these

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Correct Option: B,C
Explanation:

Mechanical energy & potential energy can be negative.

$\therefore$ Option $B$ and $C$.

If the unit of force and length be each increased by four times, then the unit of energy is increased by

physics energy and its forms idea of energy introduction to work and energy work and energy

  1. 16 times

  2. 8 times

  3. 2 times

  4. 4 times

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Correct Option: A
Explanation:

Unit of Energy = Unit of Force $\times$ Unit of length 
So if we increase unit of length and force, each by four times, then unit of energy will increase by sixteen times.