Q149 / 160 · AP EAMCET 2022 (04 Jul Shift 2) · Physics

A toroid has a non ferromagnetic core of inner radius 24 cm and outer radius 25 cm, around which 4900 turns of a wire are wound. If the current in the wire is 12 A, the magnetic field inside the core of the toroid is

  • A
    56mT
  • B
    54mT
  • C
    42mT
  • Correct answer
    D
    48mT

Solution

Here, r1 = 24 cm=24×10-2 m

r2 = 25 cm=25×10-2 m
N=4900 turns, I=12 A

Now, r=r1+r22=24.5×10-2 m
Therefore, magnetic field will be

B=μ0NI2πr=4π×10-74900122π×24.5×10-2=4800×10-5≈48 mT

Hence, the correct answer is option: 'D'.

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