# Working with magnetism, solenoid

Tags:
1. May 13, 2015

### Sox281212

1. The problem statement, all variables and given/known data
A bar magnet is held stationary (with respect to the loop of wire) at the centre of the loop with the North pole sticking out one end and the South pole sticking out the other. What happens to the size of any EMF induced in the loop once the magnet has been replaced by a magnet of twice the strength (i.e. you do the same thing, hold a stronger magnet stationary in the same position)? Explain your answer, with reference to Faraday's Law

2. Relevant equations
Faradays Law

3. The attempt at a solution
Ok so this is what i've gathered from TRYING to research online (i literally learnt nothing in class)

When the current is running through the solenoid in one direction, and the north part of the magnet is inserted towards the middle of the solenoid, the current would change directions... but how does this relate to emf? and what would increasing the magnet strength even do... would it make a stronger magnetic field? I have no clue...

2. May 13, 2015

### Staff: Mentor

Hi Sox281212, http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif [Broken]

What does Faraday's Law say about the situations described here?

Last edited by a moderator: May 7, 2017
3. May 13, 2015

### Sox281212

Thank you :)

Umm well EMF is proportional to the rate of change of the magnetic flux? :S

4. May 13, 2015

### Staff: Mentor

If I read this correctly, the situations they are comparing here both involve there being no relative movement. Is that your understanding?

5. May 13, 2015

### Sox281212

Yep! Was just wondering, while waiting for your reply I was looking up some stuff; would doubling the magnetic strength also double the EMF? -just a thought haha..

6. May 13, 2015

### Staff: Mentor

A stronger magnet could be expected to induce a greater voltage as a generalization. But for the case in question, two times zero is still zero.

7. May 13, 2015

### Sox281212

Oh okay... So.. There's No effect? :/

8. May 14, 2015

### Staff: Mentor

No relative movement means there is no induced emf.

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted