Question

A technician wearing a metal watch with a resistance of 0.0200 Ω that encloses an area of 0.00500 m2. The technician is in the presence of a uniform magnetic field with a magnitude of 4.40 T directed perpendicular to the plane of the watch. The magnetic field then drops to a magnitude of 1.32 T (in the same direction) in a time of 22.0 ms.

a. Find the current induced in the bracelet.
b. Find the power (P) delivered to the bracelet.

Answer 1

Step-by-step explanation:

Initial magnetic flux = magnetic field x area

= 4.4 x 5 x 10⁻³

= 22 x 10⁻³ weber

Final magnetic flux

= 1.32 x 5 x 10⁻³

= 6.6x 10⁻³ weber

change in magnetic flux = 15.4 x 10⁻³

emf induced = change in flux / time

= 15.4 x 10⁻³ / 22 x 10⁻³

= .7 V

current in bracelet = emf / resistance

= .7 / .02

= 35 A

b )

power = volt induced x current

= .7 x 35

= 24.5 W .