Question

The intensity of electric field required to balance a proton of mass $1.7\times {10}^{-27}kg$ and charge $1.6\times {10}^{-19}C$ is nearly.

• A. $1\times {10}^{5}V/m$
• B. $1\times {10}^{-5}V/m$
• C. $1\times {10}^{7}V/m$
• D. $1\times {10}^{-7}V/m$

Answer 1

The correct option is D $1\times {10}^{-7}V/m$

To balance proton in electric field,
$qE=mg$
or $E=\frac{mg}{q}=\frac{1.7\times {10}^{-27}\times 9.8}{1.6\times {10}^{-19}}$
$=10\times {10}^{-8}=1\times {10}^{-7}V/m$.