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QJEEM21Phf32e: JEE Main 2021 Physics - Class 12 JEEM21Phf32e Solution: A hairpin like shape as shown in figure is made by bending a…

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?

JEE Main 2021 (Online) 17th March Evening Shift Physics - Magnetic Effect of Current Question 119 English

Multiple Choice Options

  • A μ0I4πr(2−π){{{\mu _0}I} \over {4\pi r}}(2 - \pi )
  • B μ0I2πr(2−π){{{\mu _0}I} \over {2\pi r}}(2 - \pi )
  • C μ0I4πr(2+π){{{\mu _0}I} \over {4\pi r}}(2 + \pi )
  • D μ0I2πr(2+π){{{\mu _0}I} \over {2\pi r}}(2 + \pi )

Step-by-Step Verified Solution

B=μ0I4πr+μ0I4πr+μ0I4rB = {{{\mu _0}I} \over {4\pi r}} + {{{\mu _0}I} \over {4\pi r}} + {{{\mu _0}I} \over {4r}}

=μ0I2πr+μ0I4r= {{{\mu _0}I} \over {2\pi r}} + {{{\mu _0}I} \over {4r}}

⇒\Rightarrow B=μ0I4πr(2+π)B = {{{\mu _0}I} \over {4\pi r}}(2 + \pi )

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