Question

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

• A. It's kinetic energy
• B. It's momentum
• C. It's charge
• D. Magnetic fields intensity

Answer 1

Answer: (A)

It's kinetic energy

Answer 2

$r = \frac { \sqrt { 2 m K } } { q B }$ and $A = A q ^ { 2 }$ ⇒ $A = \frac { \pi ( 2 m K ) } { q ^ { 2 } b ^ { 2 } }$ $\Rightarrow A \propto K$