Question

A wire of length L carrying a current I is bent into a circle. The magnitude of the magnetic field at the centre of the circle is ____________.

विकल्प

• `(pi mu_0  "I")/"L"`

• `(mu_0  "I")/(2"L")`

• `(2pi mu_0  "I")/"L"`

• `(mu_0  "I")/(2pi "L")`

Answer 1

A wire of length L carrying a current I is bent into a circle. The magnitude of the magnetic field at the centre of the circle is `(pi mu_0  "I")/"L"`.

Explanation:

`"Magnetic field at the centre of coil B" = (mu_0  "nI")/(2"r")`

`"n" = 1  "and"  2pi"r" = "L" Rightarrow "r" = "L"/(2pi)`

`therefore "B" = (mu_0 2 pi  "I")/(2"L")`

` = (pimu_0  "I")/"L"`