For the free expansion of an ideal gas under adiabatic conditions, which of the following is true?

• Correct answer
  A

  $\mathrm{Q}=\mathrm{W}=0\mathrm{and} \mathrm{\Delta }\mathrm{U}=0$
• B

  $\mathrm{Q}\ne 0$, $\mathrm{W}=0$ and $\mathrm{\Delta U}=\mathrm{W}$
• C

  $\mathrm{Q}=0$, $\mathrm{W}\ne 0$ and $\mathrm{\Delta U}=\mathrm{W}$
• D

  $\mathrm{Q}\ne 0$, $\mathrm{W}\ne 0$ and $\mathrm{\Delta U}=0$

Hence, the correct answer is option: 'A'.