Magnetics 1 Question 12
12. Two particles $A$ and $B$ of masses $m _A$ and $m _B$ respectively and having the same charge are moving in a plane. A uniform magnetic field exists perpendicular to this plane. The speeds of the particles are $v _A$ and $v _B$, respectively and the trajectories are as shown in the figure. Then
(2001, 2M)
(a) $m _A v _A<m _B v _B$
(b) $m _A v _A>m _B v _B$
(c) $m _A<m _B$ and $v _A<v _B$
(d) $m _A=m _B$ and $v _A=v _B$
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Answer:
Correct Answer: 12. (b)
Solution:
- Radius of the circle $=\frac{m v}{B q}$ or radius $\propto m v$ if $B$ and $q$ are same.
$$ \begin{aligned} \therefore \quad(\text { Radius }) _A & >(\text { Radius }) _B \\ & m _A v _A>m _B v _B \end{aligned} $$
