Current, Polarity and EMF through circuit?

In summary, the resistor in the upper left part of the circuit is consuming energy at a rate of 24.0 J/s when the current through it flows. The resistor is 20 Ohm and the current is equal in both loops. The 2 KVL equations for the 2 loops give the following results: V-IR=ε-IR and V-KVL=0.
  • #1
TheWire247
15
0

Homework Statement



In the circuit shown in the link, the 6.0 \ohm resistor is consuming energy at a rate of 24.0 J/s when the current through it flows as shown.

A) Find the current through the ammeter A.

B) What is the polarity and emf of the battery \epsilon assuming it has negligible internal resistance?

session.masteringphysics.com/problemAsset/1267081/1/yg.19.62.jpg

Homework Equations



V=IR

V=ε-IR

The Attempt at a Solution



I am completely stuck so any help would be very much appreciated
 

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  • #2
TheWire247 said:

Homework Statement



In the circuit shown in the link, the 6.0 \ohm resistor is consuming energy at a rate of 24.0 J/s when the current through it flows as shown.

A) Find the current through the ammeter A.

B) What is the polarity and emf of the battery \epsilon assuming it has negligible internal resistance?

session.masteringphysics.com/problemAsset/1267081/1/yg.19.62.jpg

Homework Equations



V=IR

V=ε-IR

The Attempt at a Solution



I am completely stuck so any help would be very much appreciated

Your link does not appear to work. Can you please upload the JPG as an attachment? Look for the little framed painting icon in the posting window to link to a JPG.

Also, I'll move this to the Intro Physics forum. The Advanced Physics forum is for upper-division and graduate-level questions.
 
  • #3
Thank you, I have now attached the picture
 
  • #4
TheWire247 said:

Homework Statement



In the circuit shown in the link, the 6.0 \ohm resistor is consuming energy at a rate of 24.0 J/s when the current through it flows as shown.

A) Find the current through the ammeter A.

B) What is the polarity and emf of the battery \epsilon assuming it has negligible internal resistance?

session.masteringphysics.com/problemAsset/1267081/1/yg.19.62.jpg

Homework Equations



V=IR

V=ε-IR

The Attempt at a Solution



I am completely stuck so any help would be very much appreciated

First thing is to parallel combine the two 20 Ohm resistors in the upper left part of the circuit. That simplifies things a little. Then write the 2 KVL equations for the 2 loops in the circuit, and solve for the unknowns.
 
  • #5
Thank you. The problem was that I was assuming the current to be the same throughout the whole of the loops which was giving me some weird answers. Completely forgot about the junction rule.

Thank you very much for your help
 

FAQ: Current, Polarity and EMF through circuit?

What is the definition of current in a circuit?

Current is the flow of electric charge through a circuit. It is measured in amperes (A) and is the rate at which electric charge passes through a specific point in a circuit.

How is current affected by the polarity of a circuit?

The polarity of a circuit, or the direction of the electric current, determines the direction in which the electric charge flows. In a direct current (DC) circuit, the polarity is constant, while in an alternating current (AC) circuit, the polarity changes periodically.

What is the relationship between current and resistance in a circuit?

According to Ohm's law, the current in a circuit is directly proportional to the voltage and inversely proportional to the resistance. This means that as resistance increases, current decreases, and vice versa.

How does the polarity of a circuit affect the direction of the magnetic field created by the current?

The polarity of a circuit determines the direction of the magnetic field created by the current. The right-hand rule can be used to determine the direction of the magnetic field, with the thumb pointing in the direction of the current and the fingers curling in the direction of the magnetic field.

What is electromagnetic force (EMF) and how does it relate to current and polarity in a circuit?

EMF is a measurement of the energy that causes electric charge to flow in a circuit. It is directly related to the voltage and current in a circuit, and the polarity of a circuit is necessary for the creation of EMF.

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