A spherical conductor of radius 10 cm has a charge
of ``3.2 \times 10^{-7}`` C distributed uniformly. What is
the magnitude of electric field at a point 15 cm
from the centre of the sphere ?
``(\frac{1}{4 \pi \epsilon_0} = 9 \times 10^9 \frac{N m^2}{C^2})``
(1) ``1.28×10^4 N/C``
(2) ``1.28×10^5 N/C``
(3) ``1.28×10^6 N/C``
(4) ``1.28×10^7 N/C``