A negatively charged particle is revolving in a circle of radius $r.$ Out of the following which one figure represents the correct directions of $\overrightarrow{L}$ and $\overrightarrow{M}$ ($\overrightarrow{L}$ is angular momentum of particle; $\overrightarrow{M}$ is magnetic moment of the particle).

A particle of mass, $M$ and carrying charge, $Q$ is launched with initial speed, $v$ and at an angle of $\theta$ relative to the horizontal direction. When it reaches the maximum height it enters a region of the uniform magnetic field. In the region, it moves at constant velocity in the horizontal direction. Determine the direction and strength of the magnetic field.

Particle of charge $-e$ is moving with an initial velocity $\overrightarrow{v}$ when it enters midway between two plates where there gravitational force. The magnitude of the velocity of the particle if it just strikes the end of the plate?

The charges $1,2,3$ are moves in uniform transverse magnetic field then:-