Question

Two proton beams are moving with equal speed $v$ in same direction. The ratio of electron force and magnetic force between them is $-$ (Where $c_0$ is speed of light is vacuum)

• A. $\frac{c_0^2}{v^2}$
• B. $\frac{v^2}{c_0^2}$
• C. $\frac{c_0}{v}$
• D. $\frac{v}{c_0}$

Answer 1

Answer: (C)

$\frac{c_0}{v}$

electron force,

$F_e=qE$

magnetic fornce,

$F_b=qvB$

$\frac{F_e}{F_b}=\frac{qE}{qvB}$

$=\frac{\frac{E}{B}}{v}$

as, $\frac{E}{B}=c_0$

$=\frac{c_0}{v}$