A spherical conductor of radius 10 cm 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? \(\left(\frac{1}{4 \pi \varepsilon_0}=9 \times 10^9 \mathrm{Nm}^2 \mathrm{C}^{-2}\right)\)

• Correct answer
  A

  $1.28\times {10}^5 \mathrm{N} {\mathrm{C}}^{-1}$
• B

  $1.28\times {10}^6 \mathrm{N} {\mathrm{C}}^{-1}$
• C

  $1.28\times {10}^7 \mathrm{N} {\mathrm{C}}^{-1}$
• D

  $1.28\times {10}^4 \mathrm{N} {\mathrm{C}}^{-1}$

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