Question

Physics q14- I don't understand how my professor explains this question please help!

As shown in the figure, a wire and a 10-Ω resistor are used to form a circuit in the shape of a with dimensions 20 cm by 20 cm. A uniform but non-steady magnetic field is directed into the 14. plane of the circuit. The magnitude of the magnetic field is steadily decreased from 2.70 T to 0.90 Tin a time interval of 96 ms. What is the induced current in the circuit, and what is its direction through the resistor? ←20cm → A)75 mA, from b to a l. S >< >< 20cm 45 mA, from b to a C) 75 mA, from a to b D) 45 mA, from a to b E) 110 mA, from a to b 0n : Y K0

Answer 1

Resistance R = 10 ohm

Area A = 20 cm x 20 cm = 0.2 mx0.2 m = 0.04 m ²

Change in magnetic field dB = 2.7 T - 0.9 T = 1.8 T

Time interval dt = 96 m s= 0.096 s

Induced emf E = A dB / dt

= 0.04 (1.8) /(0.096)

= 0.75 volt

Induced current i = E / R

= 0.75V / 10 ohm

= 0.075 A

= 75 x10 ^-3 A

= 75 mA from b to a