Question

As shown in the figure a wire and a 10-resistor are used to form a circuit in the shape of a square, 20 cm by 20 cm. A uniform but novisteady magnetic held is directed into the plane of the circuit. The magnitude of the magnetic held is decreased from 1.50T to 0.50 T in a time interval of 3 ms. The average induced current and its direction through the resistor in this time iteratare Clasest to 20 cm 20 cm XX XX w 100 63 mA from boa. 63 m. from a to b. 38 mA from b to a 095 mA from a tob 38 mA. from a to b.

Answer 1

here,

the resistance of resistor , R = 10 ohm

area = 20 * 20 cm^2 = 0.04 m^2

change in magnetic field w.r.t , dB/dt = (1.5 - 0.5) /0.063 T/s = 15.87 T/s

the average induced current , I = area * (dB/dt ) /R

I = 0.04 * 15.87 /(10) A

I = 63 * 10^-3 A = 63 mA

as the magnetic flux through the loop is decreasing with time

using Lenz's Law

the direction fo induced field is into the page

using right hand thumb rule

the direction of induced current is CLOCKWISE

and the current in resistance is from b to a

the correct option is (63 mA , from b to a)