Question

Two particles A and B of masses mA and mB 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 vA and vB respectively and the trajectories are as shown in the figure. Then

• A. $m_A v_A < m_B v_B$
• B. $m_A v_A > m_B v_B$
• C. $m_A < v_B < $ and $ m_A v < _B$
• D. $m_A = v_B <$ and $m_A = v_B$

Answer 1

Answer: (B)

Radius of the circle$=\frac{mv}{Bq}$
or radius $\propto$ mv if B and q are same.
$ (Radius)_A > (Radius)_B$
$\therefore \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, m_A v_A > m_B v_B$