What happens when a conductor moves across a magnetic field
An electromotive force (e.m.f.) is induced in the conductor.
How can you increase the induced e.m.f.?
Move the conductor or magnet faster.
Which other factors can increase the induced e.m.f. apart from moving the conductor faster?
Use a stronger magnet or more turns in the coil. /
What rule is used to determine the relative directions of force, field, and "induced current"?
Fleming’s Right-Hand Rule
According to Fleming’s Left-Hand Rule, what does each finger represent?
(Y)Thumb → Force (motion) , (Z)First finger → Magnetic field , (X)Second finger → Current
Which law related to this statement "The direction of the induced e.m.f. always opposes the change that causes it" ?
Lenz’s Law
What is the main part that rotates in a simple a.c. generator?
A wire coil rotates in a magnetic field.
What is the function of slip rings and brushes in an a.c. generator?
To allow current to flow out of the rotating coil while keeping the connections continuous.
When is the e.m.f. at its maximum value (peak or trough) — when the coil is horizontal or vertical?
When the coil is horizontal .
When is the e.m.f. zero?
When the coil is vertical .
What shape is the magnetic field around a straight wire carrying current?
Concentric circles around the wire.
What can be used to show the magnetic field pattern around a wire?
Iron filings or a plotting compass.
How can you find the direction of the magnetic field around a current-carrying wire?
By using the right-hand grip rule.
What factors increase the strength of a solenoid’s magnetic field?
More turns of wire, larger current, and using an iron core.
What happens to the magnetic field direction if the current is reversed?
The magnetic field direction reverses.
How can you increase the turning effect on a current-carrying coil?
By increasing the number of turns on the coil / increasing the current, / increasing the strength of the magnetic field.
