Waves — Physics STD 11 Science — Question

A substance absorbs heat Q₁ in going from one state to another and releases Q₂ in coming from the second state to the first state. How much work is done by the substance and what is the change in the internal energy of the substance?

Comment on the following statement: the temperature of all the molecules in a sample of a gas is the same.

What type of energy stored in:

1. The wound spring of a watch.
2. A stretched bow while ready to project an arrow?

Is Newton's law of motion applicable for material waves? Is this applicable for electromagnetic waves?

If all the objects radiate electromagnetic energy, why do not the objects around us in everyday life become colder and colder?

On which law is the working principle of hydraulic press and hydraulic brakes based?

Is reversible process possible in nature?

If the molecules were not allowed to collide among themselves, would you expect more evaporation or less evaporation?

Light is incident normally on a small plane surface. If the surface is rotated by an angle of 30° about the incident light, does the illuminance of the surface increase, decrease or remain same? Does your answer change if the light did not fall normally on the surface? 

Should a thermometer bulb have large heat capacity or small heat capacity?