The work done in an adiabatic process is given by,
Wadiabatic=1−γnR(Tf−Ti)→ statement I is true.
For adiabatic process ΔQ=0. From the first law of thermodynamics,
ΔQ=W+ΔU
0=W+ΔU
ΔU=−W
If work is done on the gas, i.e. work is negative
∴ΔU is positive.
∴ The temperature will increase. Hence, statement II is also true.