What is the name of the ideal-gas process in which no heat is transferred?

When a gas is compressed adiabatically by a piston in a cylinder,the work done on the gas is found to be $1.5 \times 10^{4} \, J$. During this process:

$A$ gas $(\gamma = 1.5)$ is suddenly compressed to $(1/4)^{th}$ of its initial volume. Find the ratio of its final pressure to its initial pressure.

If $\Delta E_{int}$ represents the increase in internal energy and $W$ represents the work done by the system,which of the following statements is correct for a thermodynamic system?

$A$ monoatomic gas $(\gamma = 5/3)$ at a temperature of $27^{\circ}C$ is compressed adiabatically to $8/27$ of its initial volume. The change in temperature is . . . . . . $K$.

$A$ gas at normal temperature is suddenly compressed to one-fourth of its original volume. If $\frac{C_{p}}{C_{v}}=\gamma=1.5$,then the increase in its temperature is (in $K$)