\(I=q f.........(i)\)
The magnetic induction at the centre of the ring is
\(B=\frac{\mu_{0} 2 \pi I}{4 \pi R}=\frac{\mu_{0} q f}{2 R} \quad(\text { Using }(\mathrm{i}))\)
(પ્રોટોનનું દળ $=1.67 \times 10^{-27}\, kg$, પ્રોટોનનો વિજભાર $=1.69 \times 10^{-19}\,C$)