A moving magnet, a swept wire, and a switched neighboring coil all induce an EMF. What do the three have in common?
The strongest magnet in the building rests inside a coil. The field through the coil is enormous. What does the meter read?
Zero. While the magnet rests there, the field through the coil is strong, and steady.
The same strong magnet sliding out induces an EMF, because the field through the coil is then changing.
A weak magnet moving induces an EMF. A strong magnet resting induces none, however strong its field is.
A weak field that is changing induces an EMF; a strong field that is steady induces nothing.
A magnet has rested inside a coil all day, and the coil's loop is complete. How much current has flowed?
The field through the coil has not changed all day.
No EMF is induced while the magnetic field through the conductor is not changing.
With no EMF, there is nothing to drive a current.
No current has flowed at any moment of the day.
An electromagnet carries a steady 5 A, and a loop of wire rests beside it. Is an EMF induced in the loop?
A steady current makes a steady field.
The field through the loop is not changing, and nothing is moving.
No. No EMF is induced in the loop, however strong the steady field is.
A strong magnet rests motionless inside a coil. What does the voltmeter across the coil read?
Bram says a strong enough magnet induces an EMF while everything sits still. Is Bram correct?
Yuki says a moving weak magnet induces an EMF and a resting strong magnet induces none. Is Yuki correct?
A magnet rests inside a coil for an hour. Which statement about that hour is correct?
A weak magnet rests inside one coil. A far stronger magnet rests inside an identical coil. In which coil is an EMF induced?
One coil has a magnet resting inside it. An identical coil has an identical magnet sliding out of it. In which coil is an EMF induced?