RL circuit inductive reactance problem

Click For Summary

Homework Help Overview

The discussion revolves around an RL circuit problem involving a coil with given resistance and inductance, powered by a generator with variable frequency. The original poster seeks to determine the frequency at which the inductive reactance equals the resistance.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to solve for the frequency by equating the impedance to a specific value and simplifying the equation. Some participants question the relationship between angular frequency and frequency in hertz, leading to a clarification of the conversion between the two.

Discussion Status

The discussion is active, with participants exploring the relationship between angular frequency and frequency in hertz. Clarifications have been provided regarding the units involved, but no consensus on the correct frequency has been reached.

Contextual Notes

The original poster references a discrepancy between their calculated frequency and the answer provided by their teacher, indicating potential confusion regarding the conversion between angular frequency and frequency in hertz.

skate_nerd
Messages
174
Reaction score
0

Homework Statement



There's a coil, resistance R=7Ω, and inductance L=1mH, and its powered by a generator with variable frequency and Vmax=10V.
At what frequency is inductive reactance equal to resistance? (when z=R√2)

Homework Equations



z=R√2, z=√(R2+(ωL)2)

The Attempt at a Solution



I plugged in z=R√2 to z=√(R2+(ωL)2), and solved for ω. This ends up just simplifying to ω=R/L, which is 7Ω/0.001H, giving 7000Hz. But my teachers answer is 1110Hz. Am I doing something wrong here? Been stuck on this for a while.
 
Physics news on Phys.org
ω has units of radians/second.
 
Okay...isn't that basically the same thing? Frequency in measured in hertz, which is an inverse second. And also my teachers answer specifically says 1110 Hz
 
What is the equation relating Hz to radians/sec?
 
ahh. ω=2∏f. my bad...i don't know why i didnt recognize that. thanks!
 

Similar threads

The potential difference/EMF in RL circuits
  • · Replies 6 ·
Replies
6
Views
3K
Understanding a very simply RL circuit
  • · Replies 1 ·
Replies
1
Views
1K
Resonant frequency of L - R||C circuit
  • · Replies 21 ·
Replies
21
Views
2K
But is it the same for AC circuits?
  • · Replies 9 ·
Replies
9
Views
2K
Impedances of R, L, C, RL, RC, LC and RLC circuits
  • · Replies 1 ·
Replies
1
Views
2K
Change in Capacitor for largest possible Current
  • · Replies 2 ·
Replies
2
Views
2K
Calculation of current in driven series RLC circuit
  • · Replies 8 ·
Replies
8
Views
3K
The relationship of the current before and after a change.
  • · Replies 16 ·
Replies
16
Views
2K
Source Free RL circuit confusion
  • · Replies 3 ·
Replies
3
Views
1K
RLC Circuit Behavior with Changing Frequency, Capacitance, and Voltage
  • · Replies 2 ·
Replies
2
Views
2K