| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.48 |
| Score | 0% | 70% |
The voltage output of a transformer primarily depends on which of the following?
the diameter of the wire in the coils |
|
the diameter of the coils |
|
the conductor used for the wire in the coils |
|
the number of turns in the wire of the coils |
A transformer utilizes an inductor to increase or decrease the voltage in a circuit. AC flowing in a coil wrapped around an iron core magnetizes the core causing it to produce a magnetic field. This magnetic field generates a voltage in a nearby coil of wire and, depending on the number of turns in the wire of the primary (source) and secondary coils and their proximity, voltage is induced in the secondary coil.
Which of the following statements about a capacitor is false?
it is safe to touch a capacitor with your hands as long as it is small |
|
a capacitor remains charged even after the input voltage is removed |
|
to discharge a capacitor safely, use a high-wattage resistor comparable to the capacitance of the capacitor |
|
you should always discharge any capacitors before working on an electronic circuit |
The purpose of a capacitor is to retain electric charge and it will do so even after its input voltage is removed. After the input voltage is removed, the capacitor will slowly discharge but, depending on the size and characteristics of the capacitor, discharging could take from a few minutes to a few years. So, it's never safe to touch a capacitor with your hands and you should make sure to discharge any capacitors in a circuit before working on it using an appropriately high-wattage resistor or a capacitor discharge tool.
| 450 V | |
| 675 V | |
| 900 V | |
| 453 V |
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.
V = \( I \times R \) = \( 7.5 \times 60 \) = 450 V
Which of the following is a characteristic of batteries connected in parallel?
the positive terminal of one battery is connected to the negative terminal of the next |
|
total current equals the sum of the individual battery currents |
|
total current equals the average of the individual battery currents |
|
one connection is made between each adjacent battery |
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 parallel are that total voltage equals the average of the individual battery voltages, total current equals the sum of the individual battery currents, the positive terminal of one battery is connected to the positive terminal of the next, the negative terminal of one battery is connected to the negative terminal of the next, and two connections are made between each adjacent battery.
The watt is a unit of measurement for:
power |
|
resistance |
|
frequency |
|
energy |
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.