Magnetic Effects & Magnetism

JEE Main level, single correct, medium

70 of 276

Question 70 of 276

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 PP which lies on the centre of the semicircle ?

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Answer: (B) μ0I4πr(2+π)\dfrac{{\mu }_{0}I}{4\pi r}(2+\pi )

B=2×Bst.wire+BloopB=2\times {B}_{st.wire}+{B}_{loop}
B=2×μ0i4πr+μ0i2r(π2π)B=2\times \dfrac{{\mu }_{0}i}{4\pi r}+\dfrac{{\mu }_{0}i}{2r}\left(\dfrac{\pi }{2\pi }\right)
B=μ0i4πr(2+π)B=\dfrac{{\mu }_{0}i}{4\pi r}(2+\pi )

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