A square loop of side 10 cm and resistance 0.5 Ω is placed vertically in the east-west plane. A uniform magnetic field of 0.1 T is set up across the plane in the north-east direction. The magnetic field is decreased to zero in 0.7 s at a steady state. The magnitudes of current during interval is

Question

A square loop of side 10 cm and resistance 0.5 Ω is placed vertically in the east-west plane. A uniform magnetic field of 0.1 T is set up across the plane in the north-east direction. The magnetic field is decreased to zero in 0.7 s at a steady state. The magnitudes of current during interval is (A) 1 mA (B) 2 mA (C) 3 mA (D) 4 mA

Tardigrade Admin · Accepted Answer

φ0=B A cos θ =0.1 × 10-2 × cos 45° φf=0 ε=|(Δ φ/Δ t)|=(0.1 × 10-2/0.7 × √2)=1 mV , I=(ε/R)=(1 mV /0.5 Ω)=2 mA

Q. A square loop of side 10 cm and resistance 0.5Ω is placed vertically in the east-west plane. A uniform magnetic field of 0.1T is set up across the plane in the north-east direction. The magnetic field is decreased to zero in 0.7s at a steady state. The magnitudes of current during interval is

1 mA

2 mA

3 mA

4 mA

ϕ0​=BAcosθ =0.1×10−2×cos45∘ ϕf​=0 ε=∣∣​ΔtΔϕ​∣∣​=0.7×2​0.1×10−2​=1mV, I=Rε​=0.5Ω1mV​=2mA

$ϕ_{0} = B A cos θ$
$= 0.1 \times 1 0^{- 2} \times cos 4 5^{\circ}$
$ϕ_{f} = 0$
$ε = ∣ ∣ \frac{Δ ϕ}{Δ t} ∣ ∣ = \frac{0.1 \times 1 0 ^{- 2}}{0.7 \times 2} = 1 mV$ ,
$I = \frac{ε}{R} = \frac{1 mV}{0.5Ω} = 2 m A$