Question

An electron with an initial speed of $4.0\times {10}^{6}m{s}^{-1}$ is brought to rest by an electric field. The mass and charge of an electron are $9\times {10}^{-31}$kg and $1.6\times {10}^{-19}$C, respectively. Identify the correct statement.

• A. The electron moves from a region of lower potential to higher potential through a potential difference of $11.4\mu$V.
• B. The electron moves from a region of higher potential to lower potential through a potential difference of $11.4\mu$V.
• C. The electron moves from a region of lower potential to higher potential through a potential difference of $45$V
• D. The electron moves from a region of higher potential to lower potential through a potential difference of $45$V.

Answer 1

The correct option is B The electron moves from a region of higher potential to lower potential through a potential difference of $11.4\mu$V.

$\frac{m{v}^2}{2}=V\times e\to V=11.4\mu V$

since it has been stopped so it is travelling from higher potential to lower potential.