# A conducting loop around a magnetic field

A conducting loop around a magnetic field contains two light bulbs. as shown int the figure. The wires connecting the bulbs are ideal. The magnetic field is increasing rapidly.

A. Do the bulbs glow? why or why not?
B. If they glow, which bulb is brighter? or are they equally bright? explain.

at first i thought that they would glow because the B-field was changing. but then i though yes it is changing in strength but not in position relative to the loop. So then that led me to believe that there would be no induced current and the bulbs would not glow. Just trying to confirm if I'm correct or not. Thank you

link to the diagram <http://img130.imageshack.us/img130/9750/conductingloopzc9.jpg> [Broken]

Last edited by a moderator:

learningphysics
Homework Helper
at first i thought that they would glow because the B-field was changing. but then i though yes it is changing in strength but not in position relative to the loop.
Is the magnetic flux through the loop of wire with the bulbs changing? If so, then a current goes through that wire...

So even though the field is not changing position relative to the wire there is still an induced current.. hm well the flux is changing.. it is increasing as the magnetic field increases. so yes the bulbs would light up(because of what you have said) and i would assume that they would be of the same brightness. Nothing says whether or not one has more resistance than the other.

learningphysics
Homework Helper
So even though the field is not changing position relative to the wire there is still an induced current.. hm well the flux is changing.. it is increasing as the magnetic field increases. so yes the bulbs would light up(because of what you have said) and i would assume that they would be of the same brightness. Nothing says whether or not one has more resistance than the other.
yeah, I agree. seems to me like the bulbs light up and they have the same brightness.