Question

a copper ball of r= 10cm is given a charge of 4 micro coulomb.What is the electric field intensity and electric potential at (i)r= 2cm and (ii)20 cm from centre

Answer 1

E=kq/r^2=
$9 \times {10}^{9} \times 4 \times {10}^{ - 6} \div 2 \times {10}^{ - 2} =$
for 2 one divide the answer for first one with 10