During an isothermal expansion of an ideal gas,its:

Among the following,the number of state variables is $.....$
Internal energy $(U)$; Volume $(V)$; Heat $(q)$; Enthalpy $(H)$

Which of the following is correct regarding the internal energy of a substance?

Under which of the following conditions is the relation $\Delta H = \Delta E + P \Delta V$ valid for a closed system?

For a thermodynamics system,which among the following is not a state function?

Identify the correct equation relating $\Delta H$,$\Delta U$,and $\Delta T$ for $1 \text{ mole}$ of an ideal gas from the following $(R = \text{gas constant})$: