Calculating Resistance in a Circuit: Easy Physics Problem Solution

  • Thread starter Thread starter alvarez16
  • Start date Start date
  • Tags Tags
    Physics
AI Thread Summary
The discussion revolves around solving a physics problem involving the measurement of resistance in a circuit with a voltmeter and ammeter. The user successfully calculated the apparent resistance R' as 52.71 ohms but struggled with finding the correct values for the ammeter reading and voltmeter reading. They initially calculated the ammeter reading as 90.36 mA and the voltmeter reading as 4.77 V, but these results were incorrect. The problem emphasizes the need to account for the additional current through the voltmeter when determining the actual current in the circuit. Assistance is sought to accurately compute the ammeter and voltmeter readings.
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...
 
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Back
Top