Specific Heat Questions

An electric kettle takes $4\text{A}$ current at $220\text{V}$. How much time will it take to boil $1\text{kg}$ of water from temperature $20^{\circ }\text{C}$? The temperature of boiling water is $100^{\circ }\text{C}$.

Liquid oxygen at $50\text{K}$ is heated to $300\text{K}$ at constant pressure of $1\text{atm}$. The rate of heating is constant. Which one of the following graphs represents the variation of temperature with time?

The molar specific heats of an ideal gas at constant pressure and volume are denoted by $C_p$ and $C_v$, respectively. If $\gamma =\frac{C_p}{C_v}$ and $R$ is the universal gas constant, then $C_v$ is equal to:

One mole of an ideal monatomic gas undergoes a process described by the equation $P{V}^3=\text{constant}$. The heat capacity of the gas during this process is: