• Support PF! Buy your school textbooks, materials and every day products Here!

Why wouldn't rotating the handle 90 degrees induce an EMF?

  • #1
4
0

Homework Statement


upload_2018-8-24_11-9-21.png

There is some current in the bottom coil.
The question asks which would not be able to light the lightbulb
- rotating the insulating handle 90 degrees
- increasing resistance of variable resistor
-reducing resistance of variable resistor
- moving the insulating handle towards and away from the current carrying coil.

Homework Equations


emf = change in magnetic flux over time.
right hand rule for current carrying wire
B = (permeability of free space * current)/ (2pi * radius)
magnetic flux = BA

The Attempt at a Solution


Rotating the handle 90 degrees would change the area exposed to the magnetic field. All the other choices would change the strength of the magnetic field. Wouldn't all of these choices be able to light the lightbulb?
 

Attachments

Answers and Replies

  • #2
Doc Al
Mentor
44,892
1,143
Rotating the handle 90 degrees would change the area exposed to the magnetic field.
Perhaps they meant rotating the handle about a "vertical" axis, keeping the loop in the same plane.
 
  • #3
Chandra Prayaga
Science Advisor
649
148
Not clear:
1. Rotating the insulating handle which way? Around which axis? If you rotate the handle by 90 degrees about a vertical axi through the center of the coils, then nothing happens.
2. Moving the insulating handle towards and away from.... Again, which way?
 
  • #4
4
0
Thank you for the help, I did not consider the vertical axis.
 

Related Threads on Why wouldn't rotating the handle 90 degrees induce an EMF?

  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
4
Views
1K
  • Last Post
Replies
4
Views
7K
Replies
6
Views
79K
Replies
7
Views
2K
Replies
4
Views
951
Replies
1
Views
1K
Replies
8
Views
1K
  • Last Post
Replies
3
Views
9K
  • Last Post
Replies
2
Views
3K
Top