Electricity 2

Question 1

An electric circuit consists of ________, _________, and ________.

Answer 1

1. A power source 2. Conductors 3. A load

Question 2

A ______ is any device that uses electric energy.

Answer 2

Load

Question 3

EMF is measured in _____.

Answer 3

Volts

Question 4

2 factors determine how much current will flow in a DC circuit, ______, and _______.

Answer 4

Applied voltage and conductance of the wires and the load

Question 5

is how easily electricity flows in a circuit.

Answer 5

Conductance

Question 6

______ has the greatest conductance.

Answer 6

Silver

Question 7

Resistance of a material (element) depends on ________.

Answer 7

The number of free electrons it has

Question 8

The greater the cross-sectional area of a conductor, the _____ the resistance.

Answer 8

Lower

Question 9

The resistance of the load is normally much _____ than the wiring.

Answer 9

Greater

Question 10

Every power source has some internal ________.

Answer 10

Resistance

Question 11

The longer the conductor, the _____ the resistance.

Answer 11

greater

Question 12

The materials most often used for resistors are

Answer 12

carbon, and metal alloys such as nichrome, contantan, and manganam.

Question 13

Resistors are marked with a

Answer 13

tolerance.

Question 14

Current rating is often given in

Answer 14

wattage.

Question 15

Composition resistors have the advantage of _____, _____, _____.

Answer 15

small size, ruggedness, and low cost.

Question 16

Precision-type, wire-wound resistors have very ____ tolerances.

Answer 16

small

Question 17

The property of maintaining a small tolerance under all operating conditions is called

Answer 17

stability.

Question 18

When all three terminals of a variable resistor are connected in a circuit, it’s called a

Answer 18

potentiometer.

Question 19

When only two terminals are connected in a circuit, it’s called a

Answer 19

rheostat.

Question 20

Power is

Answer 20

work per second.

Question 21

1 watt =

Answer 21

1 Joule per second/ 1 amp x 1 volt

Question 22

Power ratings are not based on I²R losses, but rather on power they are able to use to do _______.

Answer 22

mechanical work

Question 23

Total power consumed is rated in

Answer 23

KWHRs.

Question 24

In a series circuit, current is

Answer 24

constant, so there are drops in voltage.

Question 25

When two batteries are connected in series, the negative terminal is connected to the positive terminal of the other battery. Current flows from the ______ to the ______ terminal.

Answer 25

negative, positive

Question 26

In a series circuit, total voltage is equal to \_\_\_\_\_.

Answer 26

The sum of the individual voltages

Question 27

If batteries are connected negative to negative, their voltages will \_\_\_\_\_.

Answer 27

cancel

Question 28

Total voltage drop in a series circuit equals

Answer 28

source voltage.

Question 29

A ______ exists if power flows from the negative terminal to the + terminal without going through a load.

Answer 29

short circuit

Question 30

The electromagnetic circuit breaker uses _______ to to open and close the circuit.

Answer 30

magnetism

Question 31

A parallel circuit has

Answer 31

more than one path for current to flow.

Question 32

In a parallel circuit, total current equals

Answer 32

the sum of the individual currents.

Question 33

In a parallel circuit, the _____ method is used to find total resistance.

Answer 33

reciprocal

Question 34

Total power consumption can be found by \_\_\_\_\_\_\_\_.

Answer 34

adding up the individual power consumptions of the circuit

Question 35

Kirchhoff's first law is

Answer 35

the sum of the voltage drops around any closed loop is equal to the sum of the EMF's in that loop.

Question 36

Resistors usually fail because

Answer 36

of heat generated by the circuit.