Need some confirmation regarding induced currents

Click For Summary
When the switch is closed in the first coil, there is initially no induced voltage in the second coil because the current is still zero at that exact moment. The first coil resists changes in current, meaning that the magnetic flux in the second coil does not change instantaneously. As the current begins to increase in the first coil, the magnetic field also starts to rise, leading to an increasing magnetic flux in the second coil over time. Therefore, at the precise moment the switch is closed, the second coil experiences no induced voltage. This understanding clarifies the relationship between the timing of the switch closure and the induced currents in the coils.
mymodded
Messages
29
Reaction score
7
Thread moved from the technical forums to the schoolwork forums
TL;DR Summary: if there are 2 coils, one with a switch and a battery. If the switch is closed, exactly at that moment when the switch is closed, there is no induced voltage in the other coil, am I correct?

1717955658585.png

In this image, exactly at the moment when we close the switch, there should only be induced voltage in the first coil (left coil), am I right? That's because the coil resists any changes in current so at t = 0, there is no current in the left circuit, thus, there is no change in magnetic flux in the second coil. Am I correct in my reasoning?

I am asking this because there was a question about this, and there was no choice saying that voltage is only induced the first coil.
 
Physics news on Phys.org
Please explain what you understand the state of the switch to be when you say "exactly at the moment when we close the switch." Is the switch open or closed at that "exact" moment? It's a binary choice: 0 or 1. Let's explore each choice. We assume that there is some resistance in the coils.

0 = switch open. Nothing has changed. There is no current anywhere and no magnetic field anywhere.

1 = switch closed. The current in the primary coil (on the left) is zero but is increasing. The magnetic field in the primary is proportional to the current, also zero and increasing. In the secondary coil (on the right) the flux from the primary is zero and increasing. (We assume that the coils are close enough to ignore the transit time of the EM signal from the left coil to the right.)

Does this resolve your question?
 
Thread 'Correct statement about size of wire to produce larger extension'
The answer is (B) but I don't really understand why. Based on formula of Young Modulus: $$x=\frac{FL}{AE}$$ The second wire made of the same material so it means they have same Young Modulus. Larger extension means larger value of ##x## so to get larger value of ##x## we can increase ##F## and ##L## and decrease ##A## I am not sure whether there is change in ##F## for first and second wire so I will just assume ##F## does not change. It leaves (B) and (C) as possible options so why is (C)...

Similar threads

Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 7 ·
Replies
7
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 7 ·
Replies
7
Views
919
Replies
1
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 0 ·
Replies
0
Views
948