7.24.F - Test: Module Seven

Question 1

Which of these is a common example of electrodynamics?
TV
dishwasher
loudspeaker
radio

Answer 1

loudspeaker

Question 2

What is the new field of study that Ampere invented to measure the current going through a wire?
electrodynamics
amperage
electromagnetic
voltage

Answer 2

electrodynamics

Question 3

When drawing a magnetic field around a bar magnet, the lines are drawn closer together where the magnetic field is __________.
nonexistent
weaker
darker
stronger

Answer 3

stronger

Question 4

The definition of an ampere or amp is ___________.
a unit of electrical potential difference
a unit of electrical force
a unit of electrical resistance
a unit of electrical current

Answer 4

a unit of electrical current

Question 5

Ampere assumed that every atom was surrounded by electrons and behaved like a small electrical circuit. This created a constant magnetic field and made every atom behave like a small ________.
battery
magnet
electron
neutron

Answer 5

magnet

Question 6

What creates the Earth’s magnetic field?
the tides
its circular movement
the Earth’s placement in the solar system
the sun’s gravity

Answer 6

its circular movement

Question 7

What happens to compass needles when a copper rod is placed at a 90-degree angle in the midst of them, and electric current is flowing through the rod?
the needles vibrate
nothing
the needles form concentric circles around the rod
the needles all point to the rod

Answer 7

the needles form concentric circles around the rod

Question 8

Jack learned that every magnet has a north end and a south end called poles. While he is playing with magnets, he notices that when he puts the north end of a magnet near the south end of another magnet, they pull together. What can Jack conclude from this observation?
only the north pole has an attractive force
only the south pole has an attractive force
opposite poles of magnets repel
opposite poles of magnets attract

Answer 8

opposite poles of magnets attract

Question 9

If the bar magnet on the left were broken in half, what statement correctly predicts how the two halves of the magnet would react to the magnet on the right?

Neither half of the broken magnet would be attracted to the magnet on the right because a magnet must have two poles.
The right side of both halves would be attracted to the magnet on the right since the south pole of each half would be facing the north pole of the other magnet.
Only the right side of the broken magnet would be attracted to the magnet on the right since it contains the south-oriented magnetic domains.
The two halves of the broken magnet would be attracted to each other, but neither would be attracted to the magnet on the right.

Answer 9

The right side of both halves would be attracted to the magnet on the right since the south pole of each half would be facing the north pole of the other magnet.

Question 10

The __________ is the largest magnet known to humanity.

Answer 10

earth

Question 11

The north arrow of a compass needle always points to _______.
Earth’s geographic north Pole
Earth’s magnetic north pole
Earth’s magnetic south pole
Earth’s geographic south Pole

Answer 11

Earth’s magnetic north pole

Question 12

What country is known to have used a ladle-and-basin, lodestone, south-pointing compass?
Italy
China
Japan
Korea

Answer 12

China

Question 13

Before satellites and radar, sailors used maps with longitude and latitude lines and _______ to plot their travels across the oceans.
stars
winds
experience
currents

Answer 13

stars

Question 14

Which scientist showed that when a current passes through a conductor, a magnetic field is created at 90 degrees to the direction of the current?
Davy
Oersted
Faraday
Ampere

Answer 14

Oersted

Question 15

Michael Faraday realized that there is a link between electricity, magnetism, and the force which can be harnessed to do _________.

Answer 15

work

Question 16

What do scientists today think of as a measure of the total electrical potential energy per unit of charge available in a source of electricity?
amp
volts
emf
watts

Answer 16

emf

Question 17

Faraday gained access to books he could study about science by working at a ____________.

doctor’s office
book bindery
library
school

Answer 17

book bindery

Question 18

A galvanometer shows ____________.
the number of amps used
the emfs in the battery
a current passing through the circuit
how many coils are in the generator

Answer 18

a current passing through the circuit

Question 19

How many volts of electricity flow through a Van de Graaff generator?
150,000
175,000
100,000
200,000

Answer 19

200,000

Question 20

Which is most likely to kill you?
high current
high voltage
a low number of amps
a high number of EMFs

Answer 20

high current

Question 21

What is the Faraday cage that your parents most likely own?
automobile
washer
refrigerator
clothes dryer

Answer 21

automobile

Question 22

The process of connecting something to the earth using a conductor is called ____________.

Answer 22

grounding

Question 23

Under what conditions do Faraday cages work best?
when they are block stable or slowly varying magnetic fields
when they are made of graphite
when they have very large holes
when they are grounded

Answer 23

when they are grounded

Question 24

Which change would result in a stronger electromagnet?

Substituting another metal for the iron core
Increasing the voltage of the battery
Reducing the number of batteries
Decreasing the number of coils around the iron core.

Answer 24

Increasing the voltage of the battery

Question 25

Bob and Sarah build an electromagnet by wrapping a wire around a nail and connecting the wire to both terminals of a battery. When they test the electromagnet, it can pick up six paper clips. Their teacher wants all groups to pick up at least 10 paper clips. What revisions could Bob and Sarah make to increase the number of paper clips their electromagnet picks up?
Increase the link of the wire
Spread the loops of the wire apart on the nail so they do not touch
Increase the number of loops of wire around the nail
Remove the nail from the center of the wire

Answer 25

Increase the number of loops of wire around the nail

Question 26

An electromagnet used in a junkyard can only pick up cars. How could the electromagnet be improved so that it could lift trucks and other large vehicles?
The electric current could be decreased and the number of wire coils could be increased.
The electric current and the number of wire coils could be increased.
The electric current could be increased and the number of wire coils could be decreased.
The electric current and the number of wire coils could be decreased..

Answer 26

The electric current and the number of wire coils could be increased.