An ac generator has emf epsilon = epsilon_m sin(omega)d t - pi/4), where epsilon

Question

An ac generator has emf epsilon = epsilon_m sin(omega)d t - pi/4), where epsilon_m = 37.5 V and omega_d = 404 rad/s. The current produced in a connected circuit is i(t) = I sin(omega_d t - 3 pi/4), where I = 730 mA. At what time after t = 0 does the generator emf first reach a maximum and the current first reach a maximum? The circuit contains a single element other than the generator. Is it a capacitor, an inductor, or a resistor? What is the value of the capacitance, inductance, or resistance, as the case may be?

Explanation / Answer

e = 37.5 sin(404t - pi/4)

a) e will be max. when sin@ = 1

and @ = npi/2

so 404t - pi/4 = pi/2

t = 5.83 x 10^-3 s Or 5.83 mSec

b) when 404t - 3pi / 4 = npi/2

3pi/4 is greater than pi/2 so using n = -1

404t - 3pi/4 = -pi/2

t = 1.94 x 10^-3 sec Or 1.94 ms

c) emf is leading with pi/2 than current.

that means it contains only inductor element.

d) for t = 0

e = 25.52 V and I = 0.516 A

Z = wd L = e/I = 25.52 / 0.516 = 51.37 ohm

L = 51.37 / 404 =0.127 H

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.