If a gas expands at constant temperature

If a gas expand at constant temperature :

If a gas expands at constnat temperature .

If a gas expands at a constant temperature it indicates that

When a gas expands at constant temperature, why does the pressure decrease? Explanin it on the basis of kinetic theory of gases.

When a gas expands at constant temperature, why does the pressure decrease? Explanin it on the basis of kinetic theory of gases.