Wednesday

January 28, 2015

January 28, 2015

Posted by **linds** on Wednesday, March 21, 2012 at 1:51am.

(a) At what frequency is the current a maximum?

2.A series circuit contains only a resistor and an inductor. The voltage V of the generator is fixed. If R = 20 Ω and L = 2.8 mH, find the frequency at which the current is one-fifth its value at zero frequency?

- physics please help!! -
**drwls**, Wednesday, March 21, 2012 at 2:01am1) Maximum current occurs at resonant frequency

f = sqrt(LC)/(2 pi)

2) Compute the angular frequency w for which the impedance magnitude is increased by a factor of 5.

I = (1/5)(V/R) = V/|Z|

= V/sqrt[R^2 + (wL^2])

V cancels out; solve for w.

Then use

f = 2 pi w

- physics please help!! -
**linds**, Wednesday, March 21, 2012 at 2:05amCan you plug in the numbers for #1 please? I'm still a little confused.

- physics please help!! -
**drwls**, Wednesday, March 21, 2012 at 6:00amSorry about that. The LC term should have been in the denominator, for problem #1.

**Answer this Question**

**Related Questions**

physics so confused - 1. A 26.0-Ω resistor, a 12.0-µF capacitor, and a 17.0...

Physics - When a resistor is connected across the terminals of an ac generator (...

Physics - When a resistor is connected across the terminals of an ac generator (...

Physics - In a series circuit, a generator (1400 Hz, 12.0 V) is connected to a ...

Physics - In a series circuit, a generator (1400 Hz, 12.0 V) is connected to a ...

physics - A source of e.m.f 110v and frequency 60hz is connected to a resistor, ...

physics - In a series circuit, a generator (1254 Hz, 13.8 V) is connected to a ...

physics - A series circuit contains only a resistor and an inductor. The voltage...

Physics - A series circuit contains only a resistor and an inductor. The voltage...

Physics Help!! - A 33.0-mH inductor has a reactance of 2.20 kΩ. (a) What is...