Question

A charged particle, having charge $q$ accelerated through a potential difference $V$ enters a perpendicular magnetic field in which it experiences a force $F$. If $V$ is increased to $5V$,the particle will experience a force

• A. $F$
• B. $5F$
• C. $0.2F$
• D. $\sqrt{5}F$

Answer 1

Answer: (D)

$\sqrt{5}F$

$\frac{1}{2}m{v}^2=qV$

So $v=\sqrt{\frac{2qV}{m}}$

$F_1=qvB=q\sqrt{\frac{2qV}{m}}B$

$F_2=q\sqrt{\frac{2q\times 5V}{m}}B$

$F_2=\sqrt{5}{F}_1$