Question

If an electron is moving at an angle of 60° to the magnetic field, the path of the motion of the electron will be:
1. Circular
2. Spiral
3. Helical
4. Linear

Answer 1

Correct Answer - Option 3 : Helical

CONCEPT.

Lorentz force:

• It is defined as the force exerted on a charged particle q moving with velocity v through an electric field E and magnetic field B.
• The entire electromagnetic force on the charged particle is called the Lorentz force and is given by

​⇒ FL = qE + qvBsinθ 

• A charged particle experiences a force when it moves in a magnetic field.

​⇒ F = qvBsinθ

Where, F =  force due to magnetic field, q = magnitude of charge, v = velocity of charge, B = magnetic field and θ = angle between v and B

• When the charged particle is moving at an angle to the magnetic field, it describes a helical path.

​EXPLANATION:

• We know that when the charged particle is moving at an angle to the magnetic field, it describes a helical path.
•  Hence, option 3 is correct.