# Electricity Review - PowerPoint PPT Presentation

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Electricity Review. A closed circuit : a.is off. b.is on. c.has a break in it. Positive electric charges : a.attract both positive charges and negative charges. b.repel positive charges and attract negative charges. c.attract positive charges and repel negative charges.

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Electricity Review

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## Electricity Review

A closed circuit:

a.is off.

b.is on.

c.hasa break in it.

Positive electric charges:

a.attractboth positive charges and negative charges.

b.repelpositive charges and attract negative charges.

c.attractpositive charges and repel negative charges.

Suppose you rub an inflated party balloon on a carpet, hold the balloon next to a wall, and discover that it "sticks" to the wall. Why did the balloon stick to the wall?

a.Likecharges on the balloon and wall cause an attraction between the two.

b.Balloonscontain a special "atomic glue" that allows them to cling to other objects.

c.Excesscharge builds up on the balloon and electrostatic forces allow the balloon and wall to be attracted to one another because they are oppositely charged.

Almost all of the electrons flowing through a battery circuit come from:

a.thewires in the circuit..

b.chemicalreactions of the light bulbs.

c.thebattery.

Electrical current will pass most easily through:

a.an insulator.

b.aconductor.

c.asemiconductor.

Which of the following could be a good conductor of electricity?

a.Ametal pot

b.Aceramic coffee cup

c.Apiece of foam packing material

Which of the following statements best describes the difference between series and parallel circuits?

a.Seriescircuits are battery circuits and parallel circuits are generator circuits.

b.Seriescircuits have a single path and parallel circuits have two or more paths.

c.Seriescircuits are used in computers and parallel circuits are used in homes.

a.series.

c.notenough information is given.

b.parallel.

d.in with Walmart’s power system to save money.

If the above charges are attracted, the second charge must be

a.neutral

c.negative

b.positive

If two light bulbs are in series and you unscrew one of them, the other light bulb will

a.becomebrighter.

c.turnoff.

b.become dimmer.

d.be short circuited.

An object becomes positive when

a.it gains protons.

c.it loses electrons.

b.it gains electrons.

d.it loses protons.

Potential differences cause

a.electronsto move from the positive terminal to the negative terminal.

b.electronsto move from the negative terminal to the positive terminal.

c.protonsto move from the positive terminal to the negative terminal.

d.protonsto move from the negative terminal to the positive terminal.

The brightness of a light bulb is determined by its filament’s

a.voltage.

c.watts.

b.amperes.

d.resistance.

Conventional current is defined as the movement of

a.positivecharge.

c.negativecharge.

b.variablecharge.

d.net charge.

The rate at which charges move through a conductor is called

a.voltage.

c.current.

b.resistance.

d.electricalpotential energy.

Individual components in a parallel circuit experience the same

a.voltage.

c.power.

b.current.

d.dissipation.

A device that protects a circuit from current overload is called a

a.resistor.c.circuit breaker.

b.capacitor.d.closed circuit

The SI unit of resistance is the

a.volt.

c.ohm.

b.ampere.

d.joule.

Potential difference is measured in

a.amperes.

c.coulombs.

b.volts.

d.joules.

Calculate the resistance of a bulb that draws 0.6 A of current with a potential difference of 3 V.

a.0.2 ohms

c.5 ohms

b.1.8 ohms

d.15 ohms

A 6.0-V battery is connected to a 24- resistor. What is the current in the resistor?

a.0.25 A

c.18 A

b.4.0 A

d.144 A

A device connected to a 120-V outlet has 2.0 A of current in it. What is the power of this device?

a.48 W

c.240 W

b.60 W

d.480 W

What is the potential difference across a resistor that dissipates 5.00 W of power and has a current of 5.0 A?

a.1.0 V

c.125 V

b.4.00 V

d.0.20 V

There is a potential difference of 12 V across a resistor with 0.25 A of current in it. The resistance of the resistor is

a.48 ohms.

c.12 ohms.

b.24 ohms.

d.0.021 ohms

A resistor has a resistance of 280 . How much current is in the resistor if there is a potential difference of 120 V across the resistor?

a.160 A

c.0.12 A

b.0.43 A

d.2.3 A

If I increase the voltage, the current will _______

If I increase the resistance the current will ________.

If I add more batteries, the brightness of the light bulbs will ________.

If my current increased, there must have been a __________ in resistance.

If I add more bulbs to a series circuit, the brightness of each bulb will _______.

### Increase or Decrease?

A path through which electricity can travel.

The pressure or push that moves electricity.

Reduces the amount of electricity flowing.

The flow of electrons thru a circuit.

When there is a break in the path; electricity can’t flow

### open circuitvoltage resistance currentclosed circuit

____36. Works as a variable resistor

____37. Stores electrical energy.

____38. Works as a light sensitive resistor.

____39. The value affects the brightness of an LED

____40. Light Emitting Diode

### CAPACITORLEDPhotocellPotentiometerresistor

____41. Another name for a solderless circuit board.

____42. Transforms electrical energy (the current flowing through it) into sound waves.

____43. Allows current to flow through it in only one direction.

____44. Provides a continuous series of pulses. Acts like a clock.

____45. Integrated Circuit

An electrician wires the entire kitchen in your home in series. Included in the circuit are the refrigerator, overhead electric lights, and the outlets to which the toaster and the microwave oven are connected. In order to keep the refrigerator operating properly, what would have to happen with the other electrical appliances and lights?

If a person were able to hold onto a high voltage wire suspended in air, what would happen?

And why?

• What is the voltage of a battery that produces 7 amps through a 4 ohm circuit?

• How much current flows thru a 12 ohm circuit when 6 volts is applied?

• How much power is used in a circuit that has 2 amps flowing through it and 9 volts applied to it?

Draw the following circuit: 2 batteries; 2 resistors in series; switch.