| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.40 |
| Score | 0% | 68% |
The formula specifying Ohm's law is which of the following?
\(V = {I \over R}\) |
|
\(V = {R \over I}\) |
|
V = IR |
|
V = I2R |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.
Which of the following is not a characteristic of a step-up transformer?
increases voltage |
|
the secondary voltage is higher than the primary voltage |
|
the primary voltage is higher than the secondary voltage |
|
has more turns in the secondary winding than in the primary winding |
As their names indicate, a step-up transformer is used to step up or increase voltage and a step-down transformer is used to step down or decrease voltage. In a step-up transformer, the secondary voltage is higher than the primary voltage and it has more turns in the secondary winding than in the primary winding.
This circuit component symbol represents a(n):
capacitor |
|
inductor |
|
potentiometer |
|
resistor |
Resistors are used to limit voltage and/or current in a circuit and can have a fixed or variable resistance. Variable resistors (often called potentiometers or rheostats) are used when dynamic control over the voltage/current in a circuit is needed, for example, in a light dimmer or volume control.
Which of the following will increase the magnetic field produced by the electric current in a wire?
construct the wire from conductive material |
|
construct the wire from insulative material |
|
wrap the wire around a ceramic core |
|
wind the wire into a coil |
A moving electric current produces a magnetic field proportional to the amount of current flow. This magnetic field can be made stronger by winding the wire into a coil and further enhanced if done around an iron containing (ferrous) core.
In an electrical circuit, resistors have fixed or __________ resistance.
parallel |
|
variable |
|
series |
|
dynamic |
Resistors are used to limit voltage and/or current in a circuit and can have a fixed or variable resistance. Variable resistors (often called potentiometers or rheostats) are used when dynamic control over the voltage/current in a circuit is needed, for example, in a light dimmer or volume control.