| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.37 |
| Score | 0% | 67% |
Which of the following will increase the magnetic field produced by the electric current in a wire?
wrap the wire around a ceramic core |
|
construct the wire from insulative material |
|
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.
| 271.5 V | |
| 270 V | |
| 135 V | |
| 540 V |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.
V = \( I \times R \) = \( 9 \times 30 \) = 270 V
From what energy do photovoltaic cells produce electrical energy?
chemical |
|
sun |
|
nuclear |
|
magnetic |
A photovoltaic cell (also known as a solar cell) converts energy from the sun into electrical energy.
A transistor works by allowing a small amount of current to control general current flow. Where is the small amount of current applied?
input |
|
base |
|
collector |
|
emitter |
The transistor is the foundation of modern electronic devices. It is made entirely from semiconductor material (making it a solid state device) and can serve many different functions in a circuit including acting as a switch, amplifier, or current regulator. A transistor works by allowing a small amount of current applied at the base to control general current flow from collector to emitter through the transistor.
What is the primary difference between a rectifier and an inverter?
a rectifier converts a DC input to AC while an inverter converts an AC input to DC |
|
a rectifier strips out the DC portion of electricity while an inverter strips out the AC portion |
|
a rectifier converts an AC input to DC while an inverter converts a DC input to AC |
|
a rectifier strips out the AC portion of electricity while an inverter strips out the DC portion |
A diode allows current to pass easily in one direction and blocks current in the other direction. Diodes are commonly used for rectification which is the conversion of alternating current (AC) into direct current (DC). Because a diode only allows current flow in one direction, it will pass either the upper or lower half of AC waves (half-wave rectification) creating pulsating DC. Multiple diodes can be connected together to utilize both halves of the AC signal in full-wave rectification.