A rod with circular cross-section area 2 cm 2 and length 40 cm is wound uniformly with 400 turns of an insulated wire. If a current of 0.4 A flows in the wire windings, the total magnetic flux produced inside windings is 4 π × 10-6 Wb. The relative permeability of the rod is (Given: Permeability of vacuum μ0=4 π × 10-7 NA -2 )

Question

A rod with circular cross-section area 2 cm 2 and length 40 cm is wound uniformly with 400 turns of an insulated wire. If a current of 0.4 A flows in the wire windings, the total magnetic flux produced inside windings is 4 π × 10-6 Wb. The relative permeability of the rod is (Given: Permeability of vacuum μ0=4 π × 10-7 NA -2 ) (A) 125 (B) 12.5 (C) (5/16) (D) (32/5)

Tardigrade Admin · Accepted Answer

φ=μ r μ0 ( N /ℓ) I × A μ r =125

$125$

$12.5$

$\frac{5}{16}$

$\frac{32}{5}$

$ϕ = μ_{r} μ_{0} \frac{N}{ℓ} I \times A$
$μ_{r} = 125$

125

12.5

165​

532​

ϕ=μr​μ0​ℓN​I×A μr​=125

$125$

$12.5$

$\frac{5}{16}$

$\frac{32}{5}$

$ϕ = μ_{r} μ_{0} \frac{N}{ℓ} I \times A$
$μ_{r} = 125$