R = 12 x 10^{-2} m, Q = 1.6 x 10^{-7}C

(a) Zero

(b) E = \(\frac{9 \times 10^{9} \times 1.6 \times 10^{-7}}{\left(12 \times 10^{-2}\right)^{2}}\)

= \(\frac{9 \times 10^{9} \times 1.6 \times 10^{-7}}{12 \times 12 \times 10^{-4}}\)

= 10^{5} NC^{-1}

(c) Here R= 18 x 10^{-2}m

Hence E = \(\frac{9 \times 10^{9} \times 1.6 \times 10^{-7}}{18 \times 18 \times 10^{-4}}\)

= \(\frac { 4 }{ 9 }\) x 10^{5} ≈ 4.4 x 10^{4} NC^{-1}