A rectangular coil of 20 turns and area of cross-section 25 cm 2 has a resistance of 100 Ω. If a magnetic field which is perpendicular to the plane of the coil changes at a rate of 1000 T / s, the current in the coil is

Question

A rectangular coil of 20 turns and area of cross-section 25 cm 2 has a resistance of 100 Ω. If a magnetic field which is perpendicular to the plane of the coil changes at a rate of 1000 T / s, the current in the coil is (A) 1.0 A (B) 50 A (C) 0.5 A (D) 5.0 A

Tardigrade Admin · Accepted Answer

The emf of coil e=-(d φ/d t) and current I=(e/R) So, the current in the coil I =(1/R) (d φ/d t)=-(1/R) (d/d t)(N B A) =-(N A/R) (d B/d t) =-(20 ×(25 × 10-4)/100) × 1000 =-0.5 A

Q. A rectangular coil of $20$ turns and area of cross-section $25 c m^{2}$ has a resistance of $100 Ω$ . If a magnetic field which is perpendicular to the plane of the coil changes at a rate of $1000 T / s$ , the current in the coil is

1.0 A

50 A

0.5 A

5.0 A

The emf of coil
$e = - \frac{d ϕ}{d t}$ and current $I = \frac{e}{R}$
So, the current in the coil
$I = \frac{1}{R} \frac{d ϕ}{d t} = - \frac{1}{R} \frac{d}{d t} (NB A)$
$= - \frac{N A}{R} \frac{d B}{d t}$
$= - \frac{20 \times ( 25 \times 1 0 ^{- 4} )}{100} \times 1000$
$= - 0.5 A$

Q. A rectangular coil of 20 turns and area of cross-section 25cm2 has a resistance of 100Ω. If a magnetic field which is perpendicular to the plane of the coil changes at a rate of 1000T/s, the current in the coil is