Question

B is constant, no current in the cube. Cube is moving with velocity \(v\). The direction of electric force on the electron inside this cube is

• A. towards \(+x\) direction
• B. towards \(-x\) direction
• C. towards \(+y\) direction
• D. towards \(-y\) direction

Hint:

Electron force direction is opposite to right-hand rule.

Answer 1

The Correct Option is B

Concept:
A moving charge in magnetic field experiences Lorentz force.
Step 1:
\[ \vec{F}=q(\vec{v}\times\vec{B}) \]
Step 2:
Use right-hand rule for \(\vec{v}\times\vec{B}\).
Step 3:
Electron has negative charge, so force direction becomes opposite.
Step 4:
Hence electron force is opposite to \(\vec{v}\times\vec{B}\).