The electric intensity due to a dipole of length 10 cm and having a charge of 500 μC, at a point on the axis 20 cm from one of the charges in air is :

• A

  $9.28 \mathrm{x} {10}^7 \mathrm{N}/\mathrm{C}$

• B

  $20.5 \mathrm{x} {10}^7 \mathrm{N}/\mathrm{C}$

• C

  $6.25 \mathrm{x} {10}^7 \mathrm{N}/\mathrm{C}$

• D

  $13.1 \mathrm{x} {10}^{11} \mathrm{N}/\mathrm{C}$