Two opposite and equal charges of $4 \times 10^{-8} \ C$ are placed at a distance of $2 \times 10^{-2} \ cm$ to form a dipole. If the dipole is placed in an external electric field of $4 \times 10^8 \ N/C$,calculate the maximum torque and the work done to rotate it by $180^{\circ}$.

• A
  $64 \times 10^{-4} \ Nm, 64 \times 10^{-4} \ J$
• B
  $32 \times 10^{-4} \ Nm, 32 \times 10^{-4} \ J$
• C
  $64 \times 10^{-4} \ Nm, 32 \times 10^{-4} \ J$
• D
  $32 \times 10^{-4} \ Nm, 64 \times 10^{-4} \ J$