AP Physics 2 : Induction
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Example Questions
Example Question #1 :Induction
Suppose the induced electromotive force of a double loop wire has a magnitude of
Write the formula for induced electromotive force.
Since there are two loops,
Solve for
Example Question #1 :Induction
A magnetic rod is inside a coil of wire which is connected to an ammeter. If the rod is stationary, which of the following statements are true?
There is no induced current
The rod induces a small current
The rod loses its magnetic field
None of these
There is induced current relative to the strength of the rod's magnetic field
There is no induced current
Current is induced in wire when the magnetic flux changes. When the magnetic rod is in motion, the flux is changing, so current is induced. If the coil were expanded or contracted with the rod still there, the flux would change and current would be induced. In our case, the rod is stationary and the coil isn't changing shape. Therefore, the flux is not changing, so there is no current being induced. Additionally, there's no reason for the rod to lose its magnetic property.
Example Question #3 :Induction
A system consists of two rails, whose resistance is zero, a conductive bar, whose resistance is also zero, and a resistor whose resistance, 0.02 Ohms. The bar remains in contact with the rails as it slides to the right with a velocity
No current will flow in the resistor
When a conductor moves through a magnetic field in such a way that it cuts through magnetic field lines, the mobile charge carriers separate due to the magnetic force on them, creating a potential
Because the positive charge in the rod feels an upward force due to the right-hand rule, the top of the rod has a greater potential than the bottom, and current flows counterclockwise around the circuit, resulting in a downward direction in the resistor.
Example Question #1 :Induction
A
There is a change in flux produced by the changing magnetic field which is given by
where
In this case the magnet is perpendicular to the cross section of the coil and so
The change in magnetic field is just the final given value minus the intial value. Faraday's Law says that an emf will be generated by a change in flux,
where
The change in time is just
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