(d) $E = \frac{q}{4\pi\varepsilon_{0}r^{2}} = 9 \times 10^{9} \times \frac{1.6 \times 10^{- 19}}{\left( 10^{- 10} \right)^{2}} = 1.44 \times 10^{11}N/C$
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.