$(i)$ | $(ii)$ | $(iii)$ |
(A) $\frac{{{\mu _0}i}}{r}$ $\otimes$ | (A) $\frac{{{\mu _0}i}}{4}\left( {\frac{1}{{{r_1}}} - \frac{1}{{{r_2}}}} \right)$ $\otimes$ | (A) $\frac{{{\mu _0}i}}{4}\left( {\frac{1}{{{r_1}}} - \frac{1}{{{r_2}}}} \right)$ $\otimes$ |
(B) $\frac{{{\mu _0}i}}{{2r}}$ $\odot$ | (B) $\frac{{{\mu _0}i}}{4}\left( {\frac{1}{{{r_1}}} + \frac{1}{{{r_2}}}} \right)$ $\otimes$ | (B) $\frac{{{\mu _0}i}}{4}\left( {\frac{1}{{{r_1}}} + \frac{1}{{{r_2}}}} \right)$ $\otimes$ |
(C) $\frac{{{\mu _0}i}}{{4r}}$ $\otimes$ | (C) $\frac{{{\mu _0}i}}{4}\left( {\frac{1}{{{r_1}}} - \frac{1}{{{r_2}}}} \right)$ $\odot$ | (C)$\frac{{{\mu _0}i}}{4}\left( {\frac{1}{{{r_1}}} - \frac{1}{{{r_2}}}} \right)$ $\odot$ |
(D) $\frac{{{\mu _0}i}}{{4r}}$ $\odot$ | (D) $0$ | (D) $0$ |
\({B_2} = \frac{{{\mu _0}}}{{4\pi }}.\frac{{\pi i}}{r}\) \(\otimes\)
\({B_{net}} = {B_1} + {B_2} + {B_3} = \frac{{{\mu _0}}}{{4\pi }}.\frac{{\pi \,i}}{r}\) \(\otimes\) \(⇒\) \({B_{net}} = \frac{{{\mu _0}i}}{{4r}} \otimes \)
\((ii)\) \((b)\) \(B_1 = B_3 = 0\)
\({B_2} = \frac{{{\mu _0}}}{{4\pi }}.\frac{{\pi \,i}}{{{r_1}}} \otimes \)
\({B_4} = \frac{{{\mu _0}}}{{4\pi }}.\frac{{\pi \,i}}{{{r_2}}} \otimes \)
So, \({B_{net}} = {B_2} + {B_4} = \frac{{{\mu _0}}}{{4\pi }}.\pi \,i\left( {\frac{1}{{{r_1}}} + \frac{1}{{{r_2}}}} \right) \otimes \)
\((iii)\) \((a)\) \(B_1 = B_3 = 0\)
\({B_2} = \frac{{{\mu _0}}}{{4\pi }}.\frac{{\pi \,i}}{{{r_1}}} \otimes \)
\({B_4} = \frac{{{\mu _0}}}{{4\pi }}.\frac{{\pi \,i}}{{{r_2}}} \otimes \) \(|{B_2}|\,\, > \,\,|{B_4}|\)
\({B_{net}} = {B_2} - {B_4} \Rightarrow {B_{net}} = \frac{{{\mu _0}i}}{4}\left( {\frac{1}{{{r_1}}} - \frac{1}{{{r_2}}}} \right) \otimes \)
$(i)$ ઇલેક્ટ્રોન $(ii)$ પ્રોટોન $(iii)$ $H{e^{2 + }}$ $(iv)$ ન્યૂટ્રોન