Question

An electric field of magnitude ${10}^5\text{N/C}$ points due west at certain point. The magnitude of the force that acts on a charge of $+2\mu C$ and $-5\mu C$ at this point respectively are

• A. $0.5\text{N}$ and $0.2\text{N}$
• B. $0.2\text{N}$ and $0.5\text{N}$
• C. $1\text{N}$ and $0.3\text{N}$
• D. $2\text{N}$ and $0.1\text{N}$

Answer 1

The correct option is B $0.2\text{N}$ and $0.5\text{N}$

Force on a charge present in an electric field is given by,
$\overrightarrow{F}=q\overrightarrow{E}$

So, force on $+2\mu \text{C}$ charge

$F_1=qE=(2\times {10}^{-6})\left({10}^5\right)$

${\overrightarrow{F}}_1=0.2\text{N}$ (due west)

Force on $-5\mu C$ charge

$F_2=(5\times {10}^{-6})\left({10}^{-5}\right)$

${\overrightarrow{F}}_2=0.5\text{N}$ (due east)

Hence, option (b) is the correct answer.