Electricity Review

Electrostatics and Circuits

If you bring a positively charged strip near a foil ball and the ball

is attracted to the strip. You know

• The foil ball is positive

• The foil ball is negative

• The foil ball is neutral

• The foil ball is either negative or neutral

• The foil ball is either positive or neutral

• The correct answer is …..

• The foil ball is either negative or neutral

The outlets in your house are connected in ______

• Series

• Parallel

• The answer is ….

• Series …

• Just kidding! Parallel is correct!

Most Christmas tree lights are connected in ______

• Series

• Parallel

• The answer is ….

• Series. Really, it is!

If you bring a charged strip near an electroscope that is neutral,

the leaves • Spread and have the same charge as the charged

strip• Spread and have the opposite charge as the

charged strip• come together and have the same charge as the

charged strip• come together and have the opposite charge as

the charged strip

The correct answers is...

• Spread and have the same charge as the charged strip

Opposite charges

• Attract

• Repel

• Fight in a cage match

The correct answers is...

• Attract!

What is the current traveling through a 20 Ohm resistor with

120V across it?• The correct answer is….

• I = V/R

• I = 120 V/20 Ω

• I = 6A

When an atom has the same number of protons as electrons, it• Is negative

• Is positive

• Is neutral

• Is all good!

• The correct answer is…

• It is neutral.

Voltage across resistors in parallel is

• The same and equal to the voltage across the source

• Varies depending on the resistance of the resistor

• Adds up to the voltage of the source.• The correct answer is….• The same and equal to the voltage across the

source

What is the current traveling through a 5 Ohm resistor and 10 Ohm resistor in series with a 30

Volt source? • 0.5 A• 1 A• 2 A• 3 A• 6 A

The correct answer is….

• Total resistance is 15 Ω (5Ω+10Ω)

• I = V/R

• I = 30 V/15Ω

• I = 2A

As I add more resistors in parallel, what happens to the

total current in the circuit?• It increases

• It decreases

• It stays the same

• It makes funny typing noises!

• The correct answer is….

• It increases.

As I add more resistors in series, what happens to the total current

in the circuit?• It increases

• It decreases

• It stays the same

• It stays quiet!

• The correct answer is….

• It decreases.

When you charge a clear plastic strip by rubbing it against a paper

towel, what is the name of this method of charging?

• Friction

• Conduction

• Induction

• Conjunction

• The correct answer is….

• Friction!

As I add more resistors in parallel, what happens to the total resistance in the circuit?

• It increases

• It decreases

• It stays the same

• The correct answer is…

• It decreases!

When an atom has more protons than electrons, it

• Is negative

• Is positive

• Is neutral

• Is out of control!

The answer is...

• It is positive!

As you add more resistors in series, what happens to the total

resistance in the circuit?• It increases

• It decreases

• It stays the same

• The answer is…

• It increases!

Two 2 Ohm resistors are in parallel with a 10 Volt source, what is voltage across one of 2

Ohm resistor• The answer is ….

• 10 Volts

A 2 Ohm resistor has 10 Volts of potential difference across it, what is the current in 2 Ohm resistor?

• 0.2 A

• 1 A

• 2 A

• 5 A

• 10 A

The correct answer is...

• I = V/R

• I = 10 V/2Ω

• I = 5A

If you add another 2Ω resistor in series with the 2Ω in the last

problem, what will be the total current?

• 0.2 A

• 2.5 A

• 2 A

• 4 A

• 10 A

• The correct answer is….

• 2.5A!

If you add another 2Ω resistor in parallel with the 2Ω in the last problem, what will be the total

current?• 0.2 A

• 1 A

• 2 A

• 4A

• 10 A

• The correct answer is….

• 10 A!

Same charges

• Attract

• Repel

• Wrestle in a royal rumble

• The answer is…

• repel! Really, it is!

When a negatively charged strip touches an electroscope and

charges it negatively, this is an example of what charging

method?• Friction • Conduction• Induction• The answer is…• Friction ….• Get real! It is conduction!

If you bring a positively charged strip near a foil ball and the ball is repelled by the strip. You know

• The foil ball is positive

• The foil ball is negative

• The foil ball is neutral

• The foil ball is either negative or neutral

• The foil ball is either positive or neutral

• The correct answer is …..

• The foil ball is positive

When you bring a charged object near a neutral object (without touching it) and

cause the charge to move within the object, this is what method of charging?

• Friction

• Conduction

• Induction

• The answer is…

• Induction!

When an atom has more electrons than protons, it is

• Negative

• Positive

• Neutral

• Cool, dude!

• The answer is...

• it is both negative and cool, dude!

Good Luck on the test, tomorrow!Here are some suggestions about how to study:

• Look over the labs, especially concentrate on the questions and their answers.

• Skim through the reading assignments and the look over the questions and their answers.

• Look over the worksheets and try solving some of the problems again without looking at your answers.