Question

When a charged particle circulates in a normal magnetic field, then the area of its circulation is proportional to

• A. its kinetic energy
• B. its momentum
• C. its charge
• D. Magnetic fields intensity

Answer 1

The correct option is A its kinetic energy

$r=\frac{\sqrt{2mK}}{qB}$ and $A=\pi \left(r^2\right)\Rightarrow A=\frac{\pi \left(2mK\right)}{q^2{B}^2}\Rightarrow A\propto K$