3 physics problems concerning inductance and rlc circuit

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Homework Help Overview

The discussion revolves around three physics problems related to inductance and RLC circuits, focusing on concepts such as resistance in superconductors, mutual inductance between conductors, and the behavior of circuits involving capacitors and inductors.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • The original poster attempts to calculate the maximum resistance of a superconducting ring using a decaying current model but encounters discrepancies in their answer. They also express uncertainty about finding mutual inductance due to differing shapes of conductors. For the third problem, they question how to derive inductance from given circuit parameters.

Discussion Status

Participants are engaging with the problems, with one suggesting that the discrepancy in the first problem may stem from a simple error. Another participant notes the need to develop a differential equation for the third problem, indicating a productive direction in the discussion.

Contextual Notes

The original poster references a specific program for calculations and expresses gratitude for the assistance received, indicating an ongoing collaborative effort in problem-solving.

Pepsi24chevy
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physics problems concerninginductance and rlc circuit

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1. "The resistance of a superconductor." In an experiment carried out by S. C. Collins between 1955 and 1958, a current was maintained in a superconducting lead ring for 2.50 yr with no observed loss. If the inductance of the ring was 3.14 10-8 H and the sensitivity of the experiment was 1 part in 109, what was the maximum resistance of the ring? (Suggestion: Treat this problem as a decaying current in an RL circuit and recall that e -x 1 - x for small x.)

So i have(R/L)t=10e-9 So i plug in and i get 3.98e-23 in which the program i am using says my answer is off by a magnitude of 10. I have recalculated it a few times and i get the same answer.


2.http://www.webassign.net/pse/p31-09.gif
On a printed circuit board, a relatively long straight conductor and a conducting rectangular loop lie in the same plane, as shown in Figure P31.9. Taking h = 0.600 mm, w = 1.30 mm, and L = 2.30 mm, find their mutual inductance

With this problem, the long straight conductor and the loop aren't the same shape, so i don't know how to go about solving this. I know the formula for mutual inductance for two wires, but that is about it.

3.http://www.webassign.net/pse/p32-50.gif
[PSE6 32.P.048.] In the circuit of Figure P32.48, the battery emf is 75 V, the resistance R is 220 , and the capacitance C is 0.500 µF. The switch S is closed for a long time, and no voltage is measured across the capacitor. After the switch is opened, the potential difference across the capacitor reaches a maximum value of 150 V. What is the value of the inductance L?

FOr this problem, i don't see how to find L using angular frequency= (1/sqrt(LC)) with the variables and info i am givin. That is the only equation i can find in my book to use.
 
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Can't comment on 2.

Re 1, being off by a factor of ten often means a simple mistake in decimal point, or a typo in the answer book. What program are you referring to?

Re 3, looks like a simple DC circuit. What you need to do is develop the differential equation that describes the behavior of the circuit (i.e. voltage, current, time) when the switch is closed.
 
web assign is the program i am referring too. Also, thanks for all the help you have given me today. It has helped me out a lot.
 
You are welcome.
 

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