Calculating Resistance in a Circuit: Easy Physics Problem Solution

  • Thread starter Thread starter alvarez16
  • Start date Start date
  • Tags Tags
    Physics
Click For Summary
SUMMARY

The discussion focuses on calculating the resistance in a circuit involving a voltmeter and an ammeter. The voltmeter has a resistance of 380 Ω, and the ammeter has a resistance of 1.18 Ω, while the circuit includes a resistance of 100 Ω and an ideal battery with an emf of 12.0 V. The correct apparent resistance R' is calculated as 52.71 Ω. However, the user struggles with determining the ammeter reading (90.36 mA) and the voltmeter reading (4.77 V), which are incorrect. The correct values need to be derived using the relationship R = V/i and considering the additional current through the voltmeter.

PREREQUISITES
  • Understanding of Ohm's Law and circuit analysis
  • Familiarity with voltmeter and ammeter characteristics
  • Knowledge of series and parallel resistance calculations
  • Basic proficiency in handling electrical units (volts, ohms, amperes)
NEXT STEPS
  • Review the principles of series and parallel circuits in electrical engineering
  • Study the effects of meter resistance on circuit measurements
  • Learn how to derive current and voltage readings in complex circuits
  • Explore practical applications of voltmeters and ammeters in real-world scenarios
USEFUL FOR

Students studying physics, electrical engineering students, and anyone interested in circuit analysis and measurement techniques.

alvarez16
Messages
2
Reaction score
0
Easy Physics problem I just can't get :(

Homework Statement



In figure 27-62, a voltmeter of resistance RV = 380 Ω and an ammeter of resistance RA = 1.18 Ω are being used to measure resistance R in a circuit that also contains a resistance R0 = 100 Ω and an ideal battery of emf ε = 12.0 V. Resistance R is given by R = V/i, where V is the voltmeter reading and i is the current in the resistance R. However, the ammeter reading is not i but rather i', which is i plus the current through the voltmeter. Thus the ratio of the two meter readings is not R but only an apparent resistance R' = V/i'. If R = 61.2 Ω, what are (a) the ammeter reading in milliamperes, (b) the voltmeter reading (in V), and (c) R'?

The Attempt at a Solution



I was able to get part C, 52.71 ohms, which is correct.

I got 90.36mA for part A, and 4.77 V for part B, but both of those are wrong.

Please help me get these!
 
Physics news on Phys.org


drawing the figure given may help...
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
755
  • · Replies 1 ·
Replies
1
Views
835
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 11 ·
Replies
11
Views
5K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 13 ·
Replies
13
Views
4K
  • · Replies 25 ·
Replies
25
Views
3K
Replies
3
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K