Question

Which of the following particle will describe the smallest circle when projected with same velocity perpendicular to magnetic field?

• A. Proton
• B. $H{e}^{+}$
• C. $L{i}^{+}$
• D. Electron

Answer 1

Answer: (D)

Electron

We know that,
radius of circular path $\left(R\right)=\frac{mv}{qB}$
Here, $v,q$ and $B$ are same.
So, $R\propto m$.
The mass of electron is minimum. So, electron will describe the smallest circle when projected with same velocity perpendicular to magnetic field.