問題一覧
1
When a bar magnet and coil approach each other, the magnetic field produced by the induced current in the coil ——- the approaching magnetic field of the bar magnet.
repels
2
is an important electrical device which is based on mutual inductance.
transformer
3
The polarity or direction of an induced current can be reversed
all the above
4
The current be induced in a circuit
when a closed circuit moves through a magnetic field.
5
The magnitude of the induced emf be increased by
Increasing the velocity of the wire as it moves through the magnetic field.
6
when you insert an iron rod inside the solenoid,
the magnetic field will increase
7
The purpose of using the Right Hand Rule with the current carrying wire is
to identify the magnetic field direction
8
Alternating current can be converted to direct current by using a device called a ——- to change the direction of the current
commutator
9
Motors are machines that convert mechanical energy to electrical energy
false
10
A generator is a machine that converts mechanical energy into electrical energy.
true
11
A …… produces a continuously changing emf.
generator
12
states that “The magnetic field of the induced current is in a direction to produce a field that opposes the change causing it
Lenz’s Law
13
What will happen when you insert an iron rod inside the solenoid
the magnetic field will increase
14
What is the purpose of using the right hand rule with the current carying wire
identifying the magnetic field direction
15
F(magnetic)
magnetic force (newton n)
16
B
magnetic field (Tesla t)
17
I
current ( ampere A)
18
L
length of current carrying wire (meter m)
19
q
charge (coulomb c)
20
V
velocity of charge motion( meter per second m/s)
21
Alternating current
is an electric current that changes direction at regular intervals.
22
Mutual inductance
The ability of one circuit to induce an emf in a nearby circuit in the presence of charging current
23
Back emf
is the emf induced in a motor’s coil that tends to reduce the current in the coil of a motor.