1142 Questions & Blanks

Question 1

The three basic parts of a voltaic cell

Answer 1

cathode
anode
electrolyte

Question 2

An electrode is a _____ that _________

Answer 2

solid

conducts an electric current

Question 3

An electrolyte conducts electricity when it _______

Answer 3

is dissolved in water

Question 4

How does an electrolyte conduct electrical charges?

Answer 4

The electrolyte forms ions and these ions conduct an electrical charge from the cathode to the anode.

Question 5

In a copper-zinc voltaic cell:

Answer 5

cathode = zinc
anode = copper
electrolyte = sulfuric acid in water

Question 6

What is a battery?

Answer 6

an arrangement of several voltaic cells connected in series or in parallel

Question 7

What is the main advantage of connecting cells in parallel rather than in series?

Answer 7

larger current intensities

Question 8

series

Answer 8

affect voltage

lower current

Question 9

parallel

Answer 9

affect amperes

higher current

Question 10

Electrochemical potential difference is

Answer 10

the difference between the electrochemical energy of a neutral atom compared to its electrochemical energy as an ion

Question 11

How are physicists able to predict a battery’s cell voltage without actually measuring it with a voltmeter?

Answer 11

by comparing the electrochemical potential of the metals involved in the chemical reaction

Question 12

Why would the combination of sodium and magnesium not make a useful voltaic cell?

Answer 12

they have a low difference of electrochemical potential

Question 13

List the three weaknesses of the zinc-copper voltaic cell

Answer 13

cannot be recharged
corrosive electrolyte spills easily
expensive electricity

Question 14

Electrolysis is

Answer 14

the separation of a molecule into its respective elements by passing an electric current through an electrolyte

Question 15

an electrolytic cell is

Answer 15

two metal plates each connected to a battery terminal and placed in an electrolyte

Question 16

Faraday’s first law of electrolysis

Answer 16

the mass of an element released at an electrode during electrolysis by a steady current is directly proportional to the quantity of electric current passing through the electrolyte

Question 17

Valence

Answer 17

a measure of the combining power of atoms

Question 18

Positive valence number

Answer 18

an atom has one or more electrons in its outer shell that is willing to give up or share with other atoms

Question 19

Negative valence number

Answer 19

the number of valence electrons that an atom seeks to obtain from other atoms

Question 20

atomic mass

Answer 20

the mass of an atom compared to the mass of a carbon-12 atom

Question 21

Faraday’s second law of electrolysis

Answer 21

the mass of a substance liberated at the electrodes during electrolysis by a steady current is proportional to the equivalent mass of that substance

Question 22

The functions of the armature, field magnet, and rings in an electric generator

Answer 22

the armature rotates between the poles of a field magnet, the field magnet induces current in the rotating armature, and the rings carry the current away from the armature to the circuit

Question 23

Why does an electric generator normally produce alternating current?

Answer 23

Each time the armature passes the opposite pole of the field magnet, the magnetic field induces current in the opposite direction

Question 24

What is a synchronous motor?

Answer 24

one whose speed is regulated at the frequency of an alternating current

Question 25

How does a transformer work?

Answer 25

transfers electric power from one coil of insulated wire to another

Question 26

Why is the measured resistance higher than the predicted resistance with alternating current?

Answer 26

self-induction

Question 27

In some devices, induction heating is used to

Answer 27

heat a metal part without heating other nonconducting parts

Question 28

How are transformers constructed to minimize eddy currents?

Answer 28

the iron core is made of numerous layers of iron separated from each other by thin coats of insulating lacquer

Question 29

How can alternating current be converted into continuous direct current?

Answer 29

using two diode rectifiers

Question 30

Describe the process of electron movement within a semiconductor

Answer 30

Electrons move toward the positive side of the crystal by going from hole to hole

Question 31

What are the advantages of semiconductor devices over regular triode and diode tubes?

Answer 31

small; use little power; generate little heat; no warm-up time; can withstand shock; do not require a hot filament or a vacuum enclosure

Question 32

Two reasons why scientists preferred direct current:

Answer 32

They were more familiar with it.

The mathematical analysis of alternating current is very complicated.

Question 33

Define self-induction

Answer 33

destructive interaction between a current and the magnetic field it produces

Question 34

Define eddy-currents

Answer 34

electric “swirls” induced in currents by changing magnetic fields