JEE PYQ: Magnetic Effects Of Current Question 4
Question 4 - 2021 (17 Mar 2021 Shift 2)
A hairpin like shape as shown in figure is made by bending a long current carrying wire. What is the magnitude of a magnetic field at point P which lies on the centre of the semicircle?
(1) $\frac{\mu_0 I}{4\pi r}(2 - \pi)$
(2) $\frac{\mu_0 I}{4\pi r}(2 + \pi)$
(3) $\frac{\mu_0 I}{2\pi r}(2 + \pi)$
(4) $\frac{\mu_0 I}{2\pi r}(2 - \pi)$
Show Answer
Answer: (2) $\frac{\mu_0 I}{4\pi r}(2 + \pi)$
Solution
$B = 2 \times B_{\text{st.wire}} + B_{\text{loop}} = 2 \times \frac{\mu_0 i}{4\pi r} + \frac{\mu_0 i}{2r} \cdot \frac{\pi}{2\pi} = \frac{\mu_0 i}{4\pi r}(2 + \pi)$.
BETA
