| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.32 |
| Score | 0% | 66% |
Which of the following is the formula for calculating electrical power?
\(P = {V \over I}\) |
|
\(P = {I \over V}\) |
|
P = IV |
|
P = I2V |
Electrical power is measured in watts (W) and is calculated by multiplying the voltage (V) applied to a circuit by the resulting current (I) that flows in the circuit: P = IV. In addition to measuring production capacity, power also measures the rate of energy consumption and many loads are rated for their consumption capacity. For example, a 60W lightbulb utilizes 60W of energy to produce the equivalent of 60W of heat and light energy.
From what energy do photovoltaic cells produce electrical energy?
nuclear |
|
sun |
|
chemical |
|
magnetic |
A photovoltaic cell (also known as a solar cell) converts energy from the sun into electrical energy.
Longer the electrical wires mean _______________ voltage drop.
greater |
|
lesser |
|
diminishing |
|
complete |
Electrical wires have a certain amount of resistance per foot. A longer wire means more resistance and a greater voltage drop.
You would measure the amount of current through a circuit with a(n):
potentiometer |
|
voltmeter |
|
battery |
|
ammeter |
Current is the rate of flow of electrons per unit time and is measured in amperes (A). An ammeter is used to measure the electric current in a circuit.
In metals, increasing the temperature typically _____________ conductivity.
increases |
|
decreases |
|
does nothing to |
|
eliminates |
All conductors have resistance and the amount of resistance varies with the element. Metals exhibit increased resistance (and, therefore, lower conductivity) as their temperature increases.