Question

Three ions $H^{+},H{e}^{+}$ and $O^{+2}$ having same kinetic energy pass through region in which there is a uniform magnetic filed perpendicular to their velocity then:

• A. $H^{+}$ will be least deflected
• B. $H{e}^{+}$ and $O^{+2}$ will be deflected equally
• C. $O^{+2}$ will be deflected most
• D. all will be deflected equally.

Answer 1

The correct option is B $H{e}^{+}$ and $O^{+2}$ will be deflected equally

Radius $r=\frac{\sqrt{2mK}}{qB}$

$⟹r\propto \frac{\sqrt{m}}{q}$

Because the deflection is inversely proportional radius so,

$\frac{q}{\sqrt{m}}=\frac{1}{1}:\frac{1}{\sqrt{4}}:\frac{2}{\sqrt{16}}=1:\frac{1}{2}:\frac{1}{2}$

Therefore, $H^{+}$ deflects most and $H{e}^{+}$ and $O^{+2}$ will be equally deflected.