Question

An electron is rotating around an infinite positive linear charge in a circle of radius $0.1 \,m$, if the linear charge density is $1 \,\mu C / m$, then the velocity of electron in $m / s$ will be

• A. $0.562 \times 10^{7}$
• B. $5.62 \times 10^{7}$
• C. $562 \times 10^{7}$
• D. $0.0562 \times 10^{7}$

Answer 1

Answer: (B)

$\frac{m v^{2}}{r}=q E$
$\frac{m v^{2}}{r}=e \cdot \frac{\lambda}{2 \pi \varepsilon_{0} r}$
$v=5.62 \times 10^{7}\, m / s$