Question

Ratio of magnetic force Fm and electric force Fe acting on a charge getting undeflected through field is:

• A. E/B
• B. B/E
• C. 1
• D. 0

Answer 1

The correct option is C 1

if the particle is undeflected, then the magnetic force equals the electric force:

$q\ast v\ast B=q\ast E$

B is the magnitude of the magnetic field

E is the magnitude of the electric field

v is the magnitude of the velocity of the particle.

If the forces are equal then:

$v=\frac{E}{B}$

For undeflected $v=1$

$\frac{E}{B}=1$