Question

Helium gas expands in a piston-cylinder in a polytropic process with n=1.67. Is the work positive, negative or zero?

Answer 1

Answer:

work will be positive when it is under polytropic expansion process

Explanation:

It states a polytropic  process with n equal to 1.67. there is a polytropic expansion that mean work is positive and if it was polytropic compression then it would   be negative

$PV^n = const$

$P_1V_1 = P_2V_2$

Also work during the process of polytropic is given as

$W_{1-2} =\frac{P_1V_1 -P_2V_2}{n-1}$

the work will be positive when it is under the polytropic expansion process