JEE Mains · Physics · STD 12 - Moving charges and magnetism
- JEE Mains 2026
- Medium
- MCQ
An infinitely long straight wire carrying current \(I\) is bent in a planer shape as shown in the diagram. The radius of the circular part is r . The magnetic field at the centre O of the circular loop is :
Pick an option to check your answer.
Answer & Solution
Correct Answer
(B) \(-\frac{\mu_0}{2 \pi} \frac{ I }{ r }(\pi-1) \hat{ i }\)
Step-by-step Solution
Detailed explanation
\(\overrightarrow{ B}_0=\overrightarrow{ B }_{ AB }+\overrightarrow{ B }_{ DE }+\overrightarrow{ B }_{ BCD }\)
\(=\frac{\mu_0 i }{4 \pi r } \hat{ i }+\frac{\mu_0 i }{4 \pi r } \hat{ i }-\frac{\mu_0 i }{2 r } \hat{ i }\)
\(=\frac{\mu_0 i }{2 \pi r } \hat{ i }-\frac{\mu_0 i }{2 r } \hat{ i }\)
\(=\frac{\mu_0 i }{2 \pi r }(1-\pi) \hat{ i }\)
\(=-\frac{\mu_0 i }{2 \pi r}(\pi-1) \hat{ i }\)
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