A spherical conductor of radius 10cm has a charge of $3.2\times {10}^{-7}\mathrm{C}$ distributed uniformly. What is the magnitude of electric field at a point 15 cm from the centre of the sphere

$\left(\frac{1}{4\mathrm{\pi }{\in }_0}=9\times {10}^9\mathrm{N}{\mathrm{m}}^2/{\mathrm{C}}^2\right)$

• A

  $1.28\times {10}^5\mathrm{N}/\mathrm{C}$

• B

  $1.28\times {10}^6\mathrm{N}/\mathrm{C}$

• C

  $1.28\times {10}^7\mathrm{N}/\mathrm{C}$

• D

  $1.28\times {10}^4\mathrm{N}/\mathrm{C}$