Question

A coil of resistance 40ohm and inductance
0.75H forms a part of a series circuit
for which the resonant frequencyis 55HZ.
if the supply is 250V, 50Hz, find
(a) line current
(b) Power factor
(c) Power consumed
(d) voltage across coil
​

Answer 1

Answer:

power consumed

Explanation:

i hope it's helpful to you

Answer 2

Given:

The resistance of the coil = 40 Ω

The inductance of the coil = 0.75 H

The resonant frequency = 55Hz

The supply voltage = 250V, 50Hz

To Find:

(a) line current

(b) Power factor

(c) Power consumed

(d) voltage across coil

​Solution:

(a) The impedance (Z) of the circuit = $\sqrt{R^2+X_L^2}$

We know that X$_L$ = ωL = 2πfL

= 2 X π X 50 X 0.75

Substituting,

Z = $\sqrt{40^2 + (100\pi X0.75)^2}$

= $\sqrt{1600+56250}$

= $\sqrt{57850}$

or Z = 240.5 Ω

The current = V/Z = 250/240.5

= 1.03 A

(b) The power factor = cosФ = R/Z

= 40/240.5

= 0.16

(c) The power consumed in the circuit = P = V X I X cosФ

= 250 X 1.03 X 0.16

= 41.2 W

(d) The voltage across the coil = Vc = I.X$_L$

= 1.03 X 235.5

= 242.5 V