A 163 ‑turn circular coil of radius 2.65 cm and negligible resistance is immersed in a uniform magnetic field that is perpendicular to the plane of the coil. The coil is connected to a 10.7 Ω resistor to create a closed circuit. During a time interval of 0.149 s, the magnetic field strength decreases uniformly from 0.481 T to zero. Find the energy, in millijoules, that is dissipated in the resistor during this time interval.

Question

Westie

Physics

6 January, 13:08

A 163 ‑turn circular coil of radius 2.65 cm and negligible resistance is immersed in a uniform magnetic field that is perpendicular to the plane of the coil. The coil is connected to a 10.7 Ω resistor to create a closed circuit. During a time interval of 0.149 s, the magnetic field strength decreases uniformly from 0.481 T to zero. Find the energy, in millijoules, that is dissipated in the resistor during this time interval.

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Waylon Mccarthy · Answer 1

change in flux = no of turns x area of coil x change in magnetic field

= 163 x π 2.65² x 10⁻⁴ x (.481 - 0)

= 1728.84 x10⁻⁴ weber

rate of change of flux = change in flux / time

= 1728.84 x10⁻⁴ /.149

= 11603 x10⁻⁴ V.

volt induced = 1.16 V

current in the circuit

= volt induced / resistance

1.16 / 10.7 =.1084 A

energy dissipated = i²Rt where i is current, R is resistance and t is time.

=.1084² x 10.7 x. 149

=.018734 J

= 18.73 mJ.