Maxwell's equations
1.[3p] What exactly goes wrong when Ampère's law in its original form is applied to a charging capacitor?
What exactly goes wrong when Ampère's law in its original form is applied to a charging capacitor?
The answer is: Two surfaces bounded by the same path give different enclosed currents, so the law has no unique answer
The answer is: Two surfaces bounded by the same path give different enclosed currents, so the law has no unique answer
The answer is: Two surfaces bounded by the same path give different enclosed currents, so the law has no unique answer
2.[2p] For a parallel plate capacitor, the displacement current between the plates equals the conduction current in the wire exactly, not approximately.
For a parallel plate capacitor, the displacement current between the plates equals the conduction current in the wire exactly, not approximately.
The answer is: True
3.[3p] A capacitor with circular plates of radius 5.0 cm is charged at 0.80 A. What is the magnetic field at the rim of the gap, in microtesla?
A capacitor with circular plates of radius 5.0 cm is charged at 0.80 A. What is the magnetic field at the rim of the gap, in microtesla?
4.[3p] The electric flux through a surface changes at V m per second. What displacement current does that represent, in microamperes?
The electric flux through a surface changes at V m per second. What displacement current does that represent, in microamperes?
5.[2p] Why is the term "displacement current" a poor name?
Why is the term "displacement current" a poor name?
The answer is: Nothing is displaced and nothing flows; it is a changing electric field
The answer is: Nothing is displaced and nothing flows; it is a changing electric field
The answer is: Nothing is displaced and nothing flows; it is a changing electric field
6.[3p] A long solenoid of radius 5.0 cm has its field rising at 0.40 T/s. What induced electric field appears 2.5 cm from the axis, in millivolts per metre?
A long solenoid of radius 5.0 cm has its field rising at 0.40 T/s. What induced electric field appears 2.5 cm from the axis, in millivolts per metre?
7.[3p] Which of these are consequences of the four equations as finally assembled?
Which of these are consequences of the four equations as finally assembled?
Select all that apply
The answer is: Charge conservation follows as a theorem rather than being assumed, A changing electric field produces a circulating magnetic field, Magnetic field lines never end
8.[3p] With no charges and no currents anywhere, why do two of the four equations still have content?
With no charges and no currents anywhere, why do two of the four equations still have content?
The answer is: A changing magnetic flux drives a circulating electric field and a changing electric flux drives a circulating magnetic field, so each can sustain the other
The answer is: A changing magnetic flux drives a circulating electric field and a changing electric flux drives a circulating magnetic field, so each can sustain the other
The answer is: A changing magnetic flux drives a circulating electric field and a changing electric flux drives a circulating magnetic field, so each can sustain the other
9.[3p] Match each equation to what it asserts.
Match each equation to what it asserts.
Gauss for electricity
Gauss for magnetism
Faraday
Ampere and Maxwell
changing magnetic flux drives electric circulation
current or changing electric flux drives magnetic circulation
no magnetic charge exists
flux out of a surface counts the charge inside
Show the answer
Gauss for electricity: flux out of a surface counts the charge inside Gauss for magnetism: no magnetic charge exists Faraday: changing magnetic flux drives electric circulation Ampere and Maxwell: current or changing electric flux drives magnetic circulation