Which of the following statements/relationships is not correct in thermodynamic change?

$\mathrm{w}=-\mathrm{nRTln}\frac{{\mathrm{V}}_2}{{\mathrm{V}}_1}$ (isothermal reversible expansion of an ideal gas)

For a system of constant volume heat involved directly changes to internal energy.

$\mathrm{\Delta U}=0$ (isothermal reversible expansion of a gas)

$\mathrm{w}=\mathrm{nRTln}\frac{{\mathrm{V}}_2}{{\mathrm{V}}_1}$