A length of 20-gauge copper wire (of diameter 0.8118 mm) is formed into a circular loop with a radius of 25.0 cm. A magnetic field perpendicular to the plane of the loop increases from zero to 10.0 mT in 0.34 s. Find the average electrical power dissipated in the process

Respuesta :

Answer:

The average electrical power dissipated in the process is 0.653 mW

Explanation:

Given;

gauge of copper wire, 20 gauge

resistivity from chart, [tex]\rho = 1.68 *10^{-8} \ ohm.m[/tex]

radius of the circular loop, r = 25 cm

magnetic field strength, B = 10 .0 mT

time, t = 0.34 s

Length of the wire, L = 2πr = 2 x π x 0.25 = 1.571 m

Area of the wire, A = πR² ⇒ R = D/2 = 0.8118 mm/ 2 = 0.4059 mm

= π(0.4059 x 10⁻³)² = 0.5177 x 10⁻⁶ m²

The resistance of the wire is given by;

[tex]R = \frac{\rho L}{A}\\\\ R = \frac{1.68*10^{-8}*1.571}{(0.5177*10^{-6})}\\\\ R = 5.098 *10^{-2} \ ohms[/tex]

Now, determine the electric potential;

[tex]E = N\frac{d\phi}{dt}\\\\ E = N(\frac{BA}{dt})\\\\ E = 1(\frac{(10*10^{-3})(\pi*0.25^2)}{0.34} )\\\\E = 0.00577 \ V[/tex]

The average power is given by;

P = V²/R

P = (0.00577²) / (5.098 x 10⁻²)

P = 6.53 x 10⁻⁴ W

P = 0.653 mW

Therefore, the average electrical power dissipated in the process is 0.653 mW