| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.37 |
| Score | 0% | 67% |
| 376.5 V | |
| 562.5 V | |
| 187.5 V | |
| 375 V |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.
V = \( I \times R \) = \( 7.5 \times 50 \) = 375 V
Which of the following will increase the magnetic field produced by the electric current in a wire?
construct the wire from insulative material |
|
wrap the wire around a ceramic core |
|
construct the wire from conductive material |
|
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.
Which of the following is not a characteristic of a step-up transformer?
the secondary voltage is higher than the primary voltage |
|
has more turns in the secondary winding than in the primary winding |
|
increases voltage |
|
the primary voltage is higher than the secondary voltage |
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.
In an electrical circuit, resistors have fixed or __________ resistance.
variable |
|
dynamic |
|
parallel |
|
series |
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 is a characteristic of batteries connected in series?
the positive terminal of one battery is connected to the positive terminal of the next |
|
total voltage equals the average of the individual battery voltages |
|
two connections are made between each adjacent battery |
|
total voltage equals the sum of the individual battery voltages |
You can multiply the voltage or the current supplied by individual batteries by connecting them together either in series or in parallel. The characteristics of batteries connected in series are that total voltage equals the sum of the individual battery voltages, total current equals the average of the individual battery currents, the positive terminal of one battery is connected to the negative terminal of the next, and one connection is made between each adjacent battery.