Question

A proton, a deuteron and an $\alpha$-particle with same kinetic energy enter perpendicularly in a uniform magnetic field, then the ratio of radii of their circular paths is

• A. 1:1:$\sqrt { 2 }$
• B. $\sqrt { 2 }$ : 1 : 1
• C. 1:$\sqrt { 2 }$: 1
• D. 1 : 2 : $\sqrt { 2 }$

Answer 1

Answer: (C)

1:$\sqrt { 2 }$: 1

Answer 2

$\because r = \frac { \sqrt { 2 \mathrm { me } } } { \mathrm { Bq } }$

Hence,

$= \frac { \sqrt { \mathrm { m } } } { \mathrm { e } } : \frac { \sqrt { 2 \mathrm {~m} } } { \mathrm { e } } : \frac { \sqrt { 4 \mathrm {~m} } } { 2 \mathrm { e } } = 1 : \sqrt { 2 } : 1$