Test flashcards

Question 1

The smallest part of an element which still retains the characteristics of that element is known as the:

Answer 1

Atom

Question 2

Atoms form ions when they:

Answer 2

gain or lose an electron

Question 3

The maximum number of electrons that can be in a valence orbit is/are

Answer 3

8

Question 4

The unit for electric charge is the

Answer 4

coulomb

Question 5

How much current would a 200 watt lamp draw from a 120 volt source?

Answer 5

200/120

1.67amps

Question 6

The term triboelectric effect refers to the generation of electricity by:

Answer 6

Friction

Question 7

Insulators can have how many electrons in their valence orbit?

Answer 7

5-8 valence

Question 8

Like electrical charges ______ each other

Answer 8

Repel

Question 9

If the distance between two point charges is decreased by 6 times. then the force between the two charges will:

Answer 9

Increase by 36 times

Question 10

Most of the electrical energy that you use in your home is produced by

Answer 10

Magnetoelectric

Question 11

If the voltage applied to a resistive circuit is doubled, the current flowing to the circuit will be

Answer 11

Doubled

Question 12

In simple words, Ohm’s Law states the current is inversely proportional to the ______ and directly proportional to the ______

Answer 12

Resistance, voltage

Question 13

A low resistance parallel path resulting in a fault condition of extremely high amperages is known as a ______ circuit.

Answer 13

short

Question 14

How many microamperes are equal to 0.0056 milliamperes?

Answer 14

5.6 microAmps

Question 15

What current range kills humans more often than any other current range?

Answer 15

100mA to 200mA

Question 16

A resistive heater draws 6.25A
when a voltage of 120V is applied
across it. What is the power rating of this heater in kilowatts?

Answer 16

120x6.25=750
750/1000= 0.75 kW

Question 17

Piezoelectricity is the product of electricity by ______

Answer 17

Pressure

Question 18

Conductors of electricity have how many electrons in their valence orbit?

Answer 18

1-3

Question 19

If 7200 joules of work are required to move 9 coulombs from charge point A to charge point B, what is the potential difference between the two?

Answer 19

7200J/9C=800V

Question 20

Name one useful application for static energy.

Answer 20

Spray painting

Question 21

Name one hazard of an electrostatic charge?

Answer 21

Explosion/Fire (igniting fuel vapors) or damage to sensitive electronic components.

Question 22

Define electrical polarity… write your answer here:

Answer 22

Polarity is determining the direction of current flow.

Question 23

What is the opposition to current flow called?

Answer 23

Resistance

Question 24

Where should a circuit breaker be located in a circuit?

Answer 24

The very beginning of the circuit

Question 25

How much voltage must be applied across a 22.5 Ohm resistor in order to dissipate 1kW?

Answer 25

P = V(squared) divided by R Answer is 150V

Question 26

How many kWh of energy are required to operate a 7200 watt dryer at 240V for 50 mins

Answer 26

Converts watts to kW and convert minutes to hours 7.2k x 0.833 = 6kW-h

Question 27

At the rate of $0.07 per kW-h, what is the cost of operating a 1.2kW. 240 V base board heater for 2 hours?

Answer 27

Convert kW to Watts Multiply watts by time Multiply total by price per kWh 2.4kWh x 0.07 = 0.168 or 0.17 Cents

Question 28

What device produces magnetoelectricity?

Answer 28

A generator

Question 29

Ammeters must be connected in a series with the load because ?

Answer 29

They have very low resistance

Question 30

Which analogue meters often has a scale that reads from right to left?

Answer 30

Ohmeter

Question 31

Which measuring instrument has both a current coil and a potential coil?

Answer 31

Wattmeter

Question 32

What meter must never be used on a live circuit?

Answer 32

Ohmeter

Question 33

If a VOM (Volt-Ohm-Milliammeter) meter does not have an OFF position, where should the range selector switch be left?

Answer 33

b) on the highest AC voltage range

Question 34

What is the resistance of a 1500W/120V hair dryer?

Answer 34

P = V(squared) divided by R R = V(squared) divided by P 9.6 ohm

Question 35

A 600W,240V rated heater is to be connected across 120V. How much power will it now develop?

Answer 35

Find resistance, use resistance to calculate power. 150 Watts will develop

Question 36

Electrical energy is calculated by multiplying:

Answer 36

voltage, current and time

Question 37

To get the most accurate voltmeter reading it is recommended that the range should be selected so that the meter reads about ______ of full scale.

Answer 37

2/3

Question 38

In electrical circuits, the rate of doing work is most commonly expressed in

Answer 38

Watts

Question 39

Generally speaking, when you increase a load in a circuit, this means that you increase the:

Answer 39

Current

Question 40

What three components must be present and operational in order for an electric circuit to allow the flow of current?

Answer 40

Source, load, conductors

Question 41

Which direction does the Ohmmeter needle move on an analog meter?

Answer 41

Right to left