Question

When cathode rays pass through a magnetic field applied transversely, the rays get deflected

• A. At right angles to the path of the beam
• B. At right angles only to the magnetic field
• C. At right angles to both the path and the magnetic field
• D. Along a parabolic path

Answer 1

The correct option is C At right angles to both the path and the magnetic field

Cathode rays are a collection of negatively charged particles.

These particles experience a force due to applied magnetic field, given by $\overrightarrow{F}=q(\overrightarrow{v}\times \overrightarrow{B})$

The the force acts perpendicular to direction of both the path($\overrightarrow{v}$) and that of magnetic field ($\overrightarrow{B}$).

Hence the deflection occurs at right angles to both the path and the magnetic field.