Transcript Electricity Review

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.
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.Like charges on the balloon and wall cause an
attraction between the two.
b.Balloons contain a special "atomic glue" that allows
them to cling to other objects.
c.Excess charge 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.the wires in the circuit..
b.chemical reactions of the light bulbs.
c.the battery.
Electrical current will pass most easily through:
a.an insulator.
b.a conductor.
c.a semiconductor.
Which of the following could be a good conductor of
electricity?
a.A metal pot
b.A ceramic coffee cup
c.A piece of foam packing material
Which of the following statements best describes the
difference between series and parallel circuits?
a.Series circuits are battery circuits and parallel circuits are
generator circuits.
b.Series circuits have a single path and parallel circuits have
two or more paths.
c.Series circuits are used in computers and parallel circuits
are used in homes.
Your house is wired in
a.series.
c.not enough 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.become brighter.
c.turn off.
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.electrons to move from the positive terminal to the negative
terminal.
b.electrons to move from the negative terminal to the positive
terminal.
c.protons to move from the positive terminal to the negative
terminal.
d.protons to 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.positive charge.
c.negative charge.
b.variable charge.
d.net charge.
The rate at which charges move through a conductor is
called
a.voltage.
c.current.
b.resistance.
d.electrical potential 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.
b.
resistor.
capacitor.
c.
d.
circuit breaker.
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 circuit
current
closed circuit
voltage
resistance
____36.
____37.
____38.
____39.
____40.
Works as a variable resistor
Stores electrical energy.
Works as a light sensitive resistor.
The value affects the brightness of an LED
Light Emitting Diode
CAPACITOR
resistor
LED
Photocell
Potentiometer
____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
555 timer
IC
bread board
speaker
diode
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.