Unit 5- Magnetism and Electricity Exam

1.

2 points

Current has a direction. By convention, current is in the direction that ___.

+ charges move

+ electrons move

- electrons move

it does not matter

2.

2 points

The symbol used to represent resistance in a schematic diagram is

a zigzag line.

one straight line.

two straight lines.

a single line that is broken

3.

2 points

A volt is a unit of

energy.

electric potential.

current.

charge.

4.

2 points

Which statement best explains why a rubber rod becomes negatively charged when rubbed with fur?

The fur is a better insulator than the rubber.

Molecules in rubber rod has a stronger attraction for electrons than the molecules in the fur.

Molecules in the fur have a stronger attraction for electrons than the molecules in the rubber rod.

The rubber rod is made is a better insulator than fur.

5.

2 points

An example of a resistor is

car battery

generator

motor

dry cell battery

6.

2 points

An example of a voltage source is

battery

light bulb

motor

wire

7.

2 points

Rubber is put around wires to protect humans from the heat generated by current flowing through the wire. Rubber is used because it is a(n) _____.

8.

2 points

The q in Coulomb's law equation stands for the _____.

mass of a charged object

# of excess electrons on the object

the current of a charged object

charge of a charged object

9.

2 points

A bird can sit on a power line with two feet because

there is no change in voltage between the birds two feet

the bird is an insulator so current cannot ever flow through it

there current flows through the bird from high to low voltage

no current actually flows in power lines

10.

2 points

A current is said to exist whenever _____.

electric charges are unbalanced

a wire is charged

a battery is present

electric charges move in a loop

11.

2 points

An electric field

is a vector quantity

has direction only

has magnitude only

is a scalar quantity

12.

2 points

A conductor differs from an insulator in that a conductor

has more voltage that travels

has more resistance for current to travel

has less voltage that travels

has less resistance for current to travel

13.

2 points

The electric field lines around a positive charge point away from the positive charge. The electric field lines around a negative charges point toward the negative charge. What type of charge (positive or negative) is used to determine the direction of electric field lines?

14.

2 points

Protons and electrons

attract each other.

not enough information

repel each other

do not interact.

15.

2 points

Magnets can be made by

placing a piece of iron near a strong electromagnet.

placing a piece of iron in a strong magnetic field.

stroking material containing iron with a magnet.

all of the above

16.

2 points

What are regions of atoms that magnetically aligned?

17.

2 points

Marie blows a fuse in her bedroom. All of the lights and appliances go out in her room. When she checks on the rest of the house, she realizes that the power is on in all of the other rooms. This is because the house is wired in ____.

18.

2 points

In order for current to flow in a circuit, you must have

two light bulbs in series.

a switch that is open.

a complete closed path for the current.

two light bulbs in parallel.

19.

2 points

During a physics lab, a plastic strip was rubbed with cotton and became positively charged. The correct explanation for why the plastic strip becomes positively charged is that ...

protons were created as the result of the charging process.

the plastic strip lost electrons during the charging process.

the plastic strip acquired extra protons from the cotton.

the plastic strip acquired extra protons during the charging process.

20.

2 points

Surrounding every magnet is

an electric field.

a magnetic field.

both A and B none of the above both A and B

none of the above

21.

2 points

Magnetic field lines surrounding a magnet are conventionally drawn

either way.

not enough information

from south to north.

from north to south.

22.

2 points

It takes 48 J of work to push a charge X from point A to point B in an electric field and 20 J of work to push charge Y from C to point D in an electric field. Which scenario describes the charge with the most potential energy?

charge X and Y have equal potential energy

charge Y

charge X

not enough information

23.

2 points

Which law identifies the force of attraction between two charges based upon the inverse square of the distance between the charges?

24.

2 points

Electric potential is defined as

gravitational potential

electrical potential energy of a charge divided by the quantity of the charge.

electrical potential energy of a charge multiplied by the quantity of the charge.

electrical potential energy.

25.

2 points

In order for there to be a flow of charge from one place to another, there must be a

conductor, such as a wire, connecting the two places.

potential difference between the two places.

Both A and B above

None of the above