Question

If an electron is moving with velocity produces a magnetic field $\vec { B }$ , then

• A. The direction of field will be same as the direction of velocity .
• B. The direction of field will be opposite to the direction of velocity.
• C. The direction of field will be perpendicular to the direction of velocity .
• D. The direction of field does not depend upon the direction of velocity .

Answer 1

Answer: (C)

The direction of field will be perpendicular to the direction of velocity .

Answer 2

According to Biot Savart’s law, The magnetic field

$\vec { B } = \frac { \mu _ { 0 } } { 4 \pi } \cdot \frac { q ( \vec { v } \times \vec { r } ) } { r ^ { 3 } }$

The direction of $\overrightarrow { \mathrm { B } }$ will be along $\overrightarrow { \mathrm { V } } \times \overrightarrow { \mathrm { r } }$ i.e. perpendicular to the plane containing and $\overrightarrow { \mathbf { r } }$