4 - Elec 2

Question 1

Basically an electrical circuit consists of ______, ______ and _____. A) B) C) D)

Answer 1

-Power source -connecting wires or conductors -load or something that uses the electrical energy

Question 2

The load is the device that takes electrical energy from the power source and ? A) B) C) D)

Answer 2

uses it to perform some useful function

Question 3

All switches perform the same basic function? A) B) C) D)

Answer 3

Opening and closing electric circuits

Question 4

The amount of voltage supplied by the source determines? A) B) C) D)

Answer 4

How much current will flow

Question 5

2 factors that determin how much current will flow in a DC circuit A) B) C) D)

Answer 5

-The voltage supplied and -How well the load and wires conduct current

Question 6

The ease with which a metal allows current to flow is? A) B) C) D)

Answer 6

conductance

Question 7

_____ has the greatest conductance? A) B) C) D)

Answer 7

Silver

Question 8

The resistance of any material depends on? A) B) C) D)

Answer 8

The number of free electrons the material has

Question 9

By choosing the proper metal for a conductor and making it with a certain cross-section and length? A) B) C) D)

Answer 9

You can produce any kind of resistance effect you want

Question 10

A unit of resistance is called? A) B) C) D)

Answer 10

Ohm

Question 11

The Greek letter ______ is often used for the symbol for the Ohm A) B) C) D)

Answer 11

Omega

Question 12

The resistance of the ______ is much greater than the resistance of the _____? A) B) C) D)

Answer 12

load; circuit wiring

Question 13

Every power source has some? A) B) C) D)

Answer 13

internal resistance

Question 14

Two possible methods of decreasing large current in a circuit with a fixed voltage are? A) B) C) D)

Answer 14

increasing the resistance of the connecting wires and adding resistors to the circuit

Question 15

The materials most often used for resistors are ______, and special metal alloys, such as nichrome, constantan and manganoan. A) B) C) D)

Answer 15

Carbon

Question 16

To account for variations resistors are marked with? A) B) C) D)

Answer 16

A tolerance

Question 17

The wattage rating on the resistor determines? A) B) C) D)

Answer 17

The maximum current a resistor can carry

Question 18

What are the advantages of a composition resistor? A) B) C) D)

Answer 18

smaller and low cost

Question 19

The property of maintaining a small tolerance under all operating conditions is called the ______ of a resistor A) B) C) D)

Answer 19

Stability

Question 20

When all 3 terminals are connected into a circuit the resistor is called A) B) C) D)

Answer 20

potentiometer

Question 21

When only the center terminal and one other terminal are used in a circuit the resistor is called? A) B) C) D)

Answer 21

Rheostat

Question 22

If you raise voltage ( E), ______ will go up. A) B) C) D)

Answer 22

Current (I)

Question 23

If you lower resistance ( R), _____ will go up. A) B) C) D)

Answer 23

Current (I)

Question 24

A good practice to always follow at this point is to think in terms of? A) B) C) D)

Answer 24

Knowns and Unknowns

Question 25

Power is the amount of ? A) B) C) D)

Answer 25

Work that can be done by a load in some standard amount of time

Question 26

A watt is the power used when? A) B) C) D)

Answer 26

One ampere of current flows through a potential difference of one volt

Question 27

The power rating of working equipment is based mostly on? A) B) C) D)

Answer 27

The power they can use to do mechanical work

Question 28

Electric companies charge their customers according to the number of? A) B) C) D)

Answer 28

Kilowatt hours of power they use

Question 29

1000 volts = A) B) C) D)

Answer 29

1 kilowatt

Question 30

1,000,000 volts = A) B) C) D)

Answer 30

1 megawatt

Question 31

In a series circuit the same _____ flows through every part A) B) C) D)

Answer 31

Current (I)

Question 32

When 2 batteries are connected in series? A) B) C) D)

Answer 32

The negative terminal of one is connected to the positive terminal of the other

Question 33

When power sources are connected in series the total voltage is? A) B) C) D)

Answer 33

The sum of the individual source voltages

Question 34

If power sources are connected so that their polarities are not in the same direction? A) B) C) D)

Answer 34

They will oppose each other

Question 35

The total voltage drop equals? A) B) C) D)

Answer 35

the source voltage

Question 36

In a series circuit there in only one current it is from? A) B) C) D)

Answer 36

The negative terminal to the positive terminal

Question 37

When current can flow from the negative terminal of the power source through the connecting wires and back to the positive terminal of the power source without going through a load, this is called? A) B) C) D)

Answer 37

short circuit

Question 38

_____ uses the principle of magnetism to open a circuit when too much current flows? A) B) C) D)

Answer 38

Electro magnetic circuit breaker

Question 39

A ____ circuit is where one or more points, the current divides and flows different paths points A) B) C) D)

Answer 39

parallel

Question 40

The total current in a parallel circuit = A) B) C) D)

Answer 40

the sum of the branches current

Question 41

This method can be used to calculate the total resistance of any combination of parallel resistance in a circuit? A) B) C) D)

Answer 41

reciprocal

Question 42

The total power consumed in a parallel circuit = A) B) C) D)

Answer 42

the sum of the power used by each individual load

Question 43

Kirchhoff’s Law No 1 A) B) C) D)

Answer 43

The sum of the voltage drops around any closed loop equals the sum of the EMF’s in that loop

Question 44

Most resistor failures result from? A) B) C) D)

Answer 44

the heat generated in the resistor by the current flow

Question 45

EMF is measured in? A) B) C) D)

Answer 45

volts

Question 46

The longer the wire? A) B) C) D)

Answer 46

the more resistance it has

Question 47

What determines the resistance of a given conductor? A) B) C) D)

Answer 47

-cross-sectional area -length of the conductor -resistance