Question

$F_g$ and $F_e$represents gravitational and electrostatic force respectively between electrons situated at a distance 10 cm. The ratio of $\frac{F_g}{F_e}$ is of the order of

• A. ${10}^{42}$
• B. $10$
• C. $1$
• D. ${10}^{-43}$

Answer 1

The correct option is D ${10}^{-43}$

Gravitational force between electrons $F_G=\frac{G(m_e{)}^2}{r^2}$
Electrostatics force between electrons $F_e=k.\frac{e^2}{r^2}$
$\frac{F_G}{F_e}=\frac{G(m_e{)}^2}{k.e^2}=\frac{6.67\times {10}^{-11}\times (9.1\times {10}^{-31}{)}^2}{9\times {10}^9\times (1.6\times {10}^{-19}{)}^2}=2.39\times {10}^{-43}$