Lenz's and Faraday's Law Induction. Help on resistor and switches

In summary: So when the switch is closed, the flux of the current in the left solenoid is greater than the flux of the current in the right solenoid. This causes a magnetic field to build up in the right solenoid. When the switch is opened, the flux of current in the left solenoid is less than the flux of current in the right solenoid. This causes the magnetic field in the right solenoid to decrease. As a result, an induced current flows from the left solenoid through the resistor to the right solenoid.
  • #1
cy19861126
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Lenz's and Faraday's Law Induction. Help on resistor and switches!

Homework Statement


Find the direction of the current in the resistor shown below a) at the instant the switch is closed b) after the switch has been closed for several minutes and c) at the instant the switch is opened

Homework Equations


V = -N(flux/t)
flux = BA


The Attempt at a Solution


Seriously, I have no idea how to start with this problem. ok, so let's look at (a) first. When switch is closed, the current is moving from the right side of the battery, through the loop and ends at the left side. Okay, and then at (b) after the switch has been closed for several minutes, what difference would it make? Maybe the value of V will decrease because of the above equation, V = flux/t? Okay, and at the instant the switch is opened, there would be no current? Somehow, I think the answer to this question is way too easy. Please check if I did anything wrong. Any help would be appreciated, thanks
 

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  • #2
Okay, I read my text and I'm guessing the answer might be as follow but I do not know why:
a) Right to left
b) no current
c) left to right
 
Last edited:
  • #3
This is all about Lenz's law. Know these laws!

When the switch is closed, we get a current in the left solenoid. This current is counter clockwise. Mind you the current is the direction of the positive charges. So this creates a magnetic field to the right, according to the right hand rule. The law says that this change in magnetic field will tend to be countered. So a magnetic field in the opposite direction is induced by the second solenoid. According to the right hand rule, the current is clockwise. Following the loops of wire of the second solenoid you will see it passes the resister from right to left.

If there is no immediate change in magnetic field of the system, there is no induced current.

Same concept as my big paragraph up. See if you can follow.
 

1. What is Lenz's Law of Induction?

Lenz's Law of Induction states that the direction of an induced current will always be such that it opposes the change that produced it. This means that when a magnetic field is applied to a conductor, it will induce a current that creates a magnetic field in the opposite direction, in order to oppose the original change.

2. What is Faraday's Law of Induction?

Faraday's Law of Induction states that a changing magnetic field will induce an electromotive force (EMF) in a conductor. This means that when the magnetic field around a conductor changes, it will induce a current in the conductor.

3. How do Lenz's and Faraday's Laws relate to each other?

Lenz's and Faraday's Laws are closely related, as they both describe the phenomenon of electromagnetic induction. Lenz's Law explains the direction of the induced current, while Faraday's Law explains the magnitude of the induced EMF. Together, they provide a comprehensive understanding of electromagnetic induction.

4. What is the role of resistors in electromagnetic induction?

Resistors play an important role in electromagnetic induction as they limit the flow of current in a circuit. This can be useful in controlling the strength of the induced current, and in preventing damage to the circuit. In some cases, resistors are intentionally added to a circuit to increase the strength of the induced current.

5. How do switches affect electromagnetic induction?

Switches can affect electromagnetic induction by either allowing or interrupting the flow of current in a circuit. When a switch is closed, it completes the circuit and allows the induced current to flow. When a switch is open, it interrupts the circuit and prevents the flow of current, which will stop the induction process.

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