Question

An electron moving horizontally from left to right in a region where a magnetic field exists vertically downwards describes: (when seen from above)

• A. Horizontal clock-wise circular path
• B. Horizontal anti clock-wise circular path
• C. Vertical clock-wise circular path
• D. Vertical anti clock-wise circular path

Answer 1

The correct option is A Horizontal clock-wise circular path

Given : An electron moving horizontally from left to right in a region where a magnetic field exists vertically downwards.

Solution :

Formula for force on moving charge is $\overrightarrow{F}=q(\overrightarrow{V}\times \overrightarrow{b})$

When we will take cross product of velocity and magnetic field then we will get force acting on the charge as seen from above is in anticlockwise direction but we have an electron here so there will be negative sign on charge which means force will be in opposite direction so the force as seen from above will be in clockwise direction.

The Correct Opt : A