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Review sheet for electricity Chapter 7
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Different household appliances use ____________ ___________ at different rates.
An _______________ is a material that doesn’t allow electrons to flow through it easily.
The presence of a ________ __________ charge can be detected by an electroscope.
A lightning bolt occurs when billions of __________ are transferred at the same time.
Lightning produces air temperatures hotter than the __________ surface.
The rearrangement of electrons on a neutral object caused by a nearby charged object is called
charging by ___________________.
7) _____________ difference is measured in volts.
8) The unit used to measure _____________ is the ampere.
9) The carbon rod forms the positive terminal of a ____________ cell.
10) A____________ is a device used to keep electrical circuits from overheating.
11) The unit of electrical energy is the _____________________________.
12) Resistance is the tendency for a material to __________ the flow of electrons.
13) Resistance is measured in a unit called the ___________.
14) The statement that current is equal to the voltage difference divided by the resistance is known as
___________ __________.
15) A path that allows __________ route for an electric current is called a series circuit.
16) Electric charge that has ____________ on an object is referred to as static electricity.
17) A circuit that has two or more branches for electrons to follow is a __________ _________.
18) The _____________at which an electrical device converts energy from one form to another is called
electrical power.
19) A ___________ discharge differs from an electric current in that a static discharge lasts for only a
fraction of a second.
20) A material through which electron do __________ is a conductor.
21) If the leaves of an electroscope spread apart, it indicates that the leaves of the electroscope have
received a ___________.
22) Lightning is a large discharge of _________ _______________.
23) The ___________ rod in a standard D-cell serves as a conductor to transfer electrons.
24) One source of ____________ electric current is a dry cell.
25) A _________ ___________ is a device designed to open an overload circuit and prevent overheating.
26) A fuse contains a piece of metal that __________ if the current becomes too high.
27) A circuit breaker contains a piece of metal that __________ when it gets too hot.
28) An electroscope detects the presence of _________ ______________.
29) There is a ___________ force between two charged objects when charges are of like sign.
30) There is an___________ force between two charged objects when charges are of unlike sign.
31) When a glass rod is rubbed with silk and becomes positively charged, electrons are______________
from the silk.
32) When there is an equal amount of positive and negative charges on an object, the object is
______________________.
33) The _________ ___________ between charged objects either attractive or repulsive.
34) Electric forces varies depending on the charge and ___________between charged objects.
35) Every charged particle produces an ___________ field.
36) The electric field lines around a negatively charged particle always point ________________.
37) Electric field lines point toward a negative charge, point ___________ from a positive charge and never
cross one another.
38) Electric field lines indicate both ____________ and relative _______________
39) When compared to a -2 charge, there are ___________ as many field lines pointing outward from a +4
charge.
40) Potential difference is measured in __________________.
41) All of the following are electric cells: electrochemical, ___________, and photoelectric.
42) Batteries typically have one _________ and one ____________ terminal.
43) An electric current is produced when charges are accelerated by an electric field to move to a position
of potential energy that is l________________.
44) ______________ is the rate at which charges move through a conductor.
45) Potential differences cause _____________ to move from the negative terminal to the positive
terminal.
46) The brightness of a light bulb is determined by its ___________________ resistance.
47) Resistance is caused by_________ _____________.
48) Whether or not charges will move in a material depends partly on how tightly electrons are held in the
atoms of the material.
49) All of the following affect a materials resistance: length, temperature, and type of material.
50) What happens to the resistance of a superconductor when its temperature drops below the critical
temperature? Resistance drops to zero.
51) Rank the following from least resistance to most resistance: insulator, conductors, superconductors,
semiconductors.
52) Appliances connected so that they form a single pathway for charges to flow are connected in a
___________ __________________.
53) What is the equation for power: ________________
54) What is the equation for electrical energy: _______________
55) A flashlight bulb with a potential difference of 4.5 V across its filament has a power output of 8.0 W.
How much current is in the bulb filament?
56) What is the potential difference across a resistor that dissipates 5.00 W of power and has a current of
5.0A?
57) There is a potential difference of 12 V across a resistor with a 0.25 A of current in it. The resistance of
the resistor is 48 Ω.
58) A 13 Ω resistor has 0.050 A of current in it. What is the potential difference across the resistor?
59) A resistor has a resistance of 280 Ω. How much current is in the resistor if there is a potential
difference of 120 V across the resistor?
60) A set of electric trains are powered by a 9V battery. What is the resistance of the trains if they draw
3.0 A of current?
61) If a lamp is measured to have a resistance of 45 Ω when it operates at a power of 80.0 W, what is the
current of the lamp?
62) An electric toaster has a power rating of 1100 W at 110 V. What is the resistance of the heating coil?
63) If a lamp is measured to have a resistance of 120 Ω when it operates at a power of 1.00 x 10 2 W, what
is the potential difference across the lamp?
64) If a 325W heater has a current of 6.00 A, what is the resistance of the heating element?
65) A color television draws about 2.5 A when it is connected to a 120 V outlet. Assuming electrical energy
costs $0.060 per kWh, what is the cost of running the television for exactly 8 hours?
66) A microwave draws 5.0 A when it is connected to a 120 V outlet. If electrical energy cost $0.090 /kWh,
what is the cost of running the microwave for exactly 6 hours?
67) A hair dryer draws 11 A when it is connected to 120 V. If electrical energy costs $0.09 kWh, what is the
cost of using the hair dryer for exactly 15 minutes.
68) If a 75 W light bulb operates a voltage of 120 V, what is the current in the bulb?
69) The reading on an electric meter was 2,345 kWh, and one month later it was 3,456 kWh. How much
electrical energy was used during the one-month period?
70) The reading on an electric meter was 2,345 kWh, and one month later was 3,456 kWh. How much was
the electric bill if the electricity costs $0.10 per kilowatt-hour?
71) An air conditioner uses 1,800 W of power when plugged into a wall socket that operates at a voltage
of 210 V. What is the current flowing through the air conditioner?
72) What is the current that flows through a 100-W light bulb if it is connected to a 110-V source?