d
\(\,r\,\, = \,\,0.5\,\,\mathop A\limits^ \circ  \,,\,\,V\,\, = \,\,2.2\,\, \times \,\,{10^6}m/\sec \)

\(B\, = \,\,\frac{{{\mu _0}ev}}{{4\,\pi \,{r^2}}}\,\, = \)  

\( = \,\,\frac{{{{10}^{ - 7}} \times \,\,1.6\,\, \times \,\,{{10}^{ - 19}} \times \,\,2.2\,\, \times \,\,{{10}^6}}}{{25\,\, \times \,\,{{10}^{ - 22}}}}\)

\( = \,\,14.08\,\,\)  ટેસ્લા