Question

Solve:

$9\times {10}^9\times \frac{1.6\times {10}^{-19}\times 1.6\times {10}^{-19}}{(5.3\times {10}^{-11}{)}^2}.$

Answer 1

$9\times {10}^9\times \frac{1.6\times {10}^{-19}\times 1.6\times {10}^{-19}}{5.3\times {10}^{-11}\times 5.3\times {10}^{-11}}$

$=\frac{9\times 1.6\times 1.6}{5.3\times 5.3}\times \frac{{10}^9\times {10}^{-19}\times {10}^{-19}}{{10}^{-11}\times {10}^{-11}}$

$=0.82\times {10}^{9-38+22}$

$=8.2\times {10}^{-8}$