Question

A proton is travelling along the x-direction with velocity $5\times {10}^{6}m{s}^{-1}$. The magnitude of force experienced by the proton in a magnetic field $B=(0.2\hat{i}+0.4\hat{k})$ tesla is

• A. $3.2\times {10}^{-13}N$
• B. $5.3\times {10}^{-13}N$
• C. $3.2\times {10}^{13}N$
• D. $6.3\times {10}^{-13}N$
• E. $3.5\times {10}^{-12}N$

Answer 1

The correct option is C $3.2\times {10}^{13}N$

Given, $B=(0.20\hat{i}+0.4\hat{k})$ tesla
and $v=5\times {10}^{6}m{s}^{-1}$
We know that,
Net force, $F=q(v\times B)$
or $F=qvB\cdot (\hat{i}\times \hat{k})$
$\Rightarrow F=1.6\times {10}^{-19}\times 5\times {10}^6\times 0.4$
$\therefore F=3.2\times {10}^{-13}N$.