Physical science moles Chapter 8
When a pair of 1 ohm resistors are connected in series, their combined resistance is
2 ohms, and when in parallel, 1/2 ohm
A 60-W light bulb is connected to a 120-V plug. What is the current in the light bulb?
0.5 A
If you use 10 J of work to push a charge into an electric field and then release the charge, as it flies past its starting position, its kinetic energy is
10 J
If you use 10 J of work to push a coulomb of charge into an electric field, its voltage with respect to its starting position is
10 V
A certain bulb with a resistance of 95 ohms is labeled "150 W." This bulb was designated for use in a
120-V circuit
Two charges separated by one meter exert a 1-N force on each other. If the charges are pushed to 0.25-m separation, the force on each charge will be
16 N
The source of electrons lighting an incandescent ac light bulb is
atoms in the light bulb filament
An electron and a proton
attract each other
The current in a 100-W bulb connected to a 120-V source is
None of the above
A woman experiences an electrical shock. The electrons making the shock come from the
Womans body
In a common dc circuit, electrons move at speeds of
a fraction of a centimeter per second
An uncharged pith ball is suspended by a nylon fiber. When a negatively charged rubber rod is brought nearby, without touching it, the pith ball
becomes polarized
Every proton in the universe is surrounded by its own
both of these
The electrical forces between charges depends on the
both of these
In an ac circuit, the electric field
changes magnitude and direction with time
An ampere is a unit of electrical
current
As more lamps are put into a series circuit, the overall current in the power source
decreases
A positive charge and a negative charge held near each other are released. As they move, the force on each particle
increases
As more lamps are put into a parallel circuit, the overall current in the power source
increases
Heat a copper wire and its electric resistance
increases
Charge carriers in a metal are electrons rather than protons because electrons are
loosely bound
A wire that carries an electric current
may be electrically charged
Rub electrons from your hair with a comb and the comb becomes
negatively charged
A difference between electric forces and gravitational forces is that electrical forces include
replusive interactions
In an electric circuit, the safety fuse is connected to the circuit in
series
To be safe in the unlikely case of a lightning strike, it is best to be inside a building framed with
steel
Compared to the amount of electric current that flows in the filament of a lamp, the amount of current that flows in the connecting wire is
the same
An electron is pushed into an electric field where it acquires a 1-V electrical potential. If two electrons are pushed the same distance into the same electric field, the electrical potential of the two electrons is
1 V
When a battery does 24 J of work on 10 C of charge, the voltage it supplies is
2.4 V
Coulomb's Law
a law stating that like charges repel and opposite charges attract, with a force proportional to the product of the charges and inversely proportional to the square of the distance between them.
Two lamps, one with a thick filament and one with a thin filament, are connected in parallel to a battery. The voltage is greatest across the lamp with the
both voltages are the same
Electrons move in an electrical circuit
by interacting with an established electric field
Stretch a copper wire so that it is thinner and the resistance between its ends
increases
To say that electric charge is conserved means that no case has ever been found where
is a whole-number multiple of the charge of one electron
To say that an object is electrically polarized is to say
its charges have been rearranged
Compared to the resistance of two resistors connected in series, the same two resistors connected in parallel have
less resistance
When a light switch is turned on in a dc circuit, the average speed of electrons in the lamp is
less than 1 cm/s
When two lamps are connected in parallel to a battery, the electrical resistance that the battery senses is
less than the resistance of either lamp
Compared to a single lamp connected to a battery, two lamps connected in parallel to the same battery will carry
more current
Connect a pair of lamps in series and you draw current from the connecting battery. Connect the same lamps in parallel and you draw
more current
A 10 ohm resistor has 5 A current in it. What is the voltage across the resistor?
more than 20 V
When two lamps are connected in series to a battery, the electrical resistance that the battery senses is
more than the resistance of either lamp
Strip electrons from an atom and the atom becomes a
positive ion
A positive ion has more
protons then electrons
A main difference between gravitational and electric forces is that electrical forces
repel or attract
The source of electrons in an ordinary electrical circuit is
the electrical conductor itself
There are electrons in the filament of the ac lamp in your bedroom. When you turn on the lamp and it glows, the glowing comes from
the same electrons
Two lamps, one with a thick filament and one with a thin filament, are connected in parallel to a battery. The current is largest in the lamp with the
thick filament
Compared to the filament thickness of a 60-W light bulb, the filament of a 100-W light bulb will be
thicker
A circuit is powered with a battery. Current flows
through both the battery and the rest of the circuit.
If you plug an electric toaster rated at 110-V into a 220-V outlet, current in the toaster will be about
twice what it should be
Alternating current is normally produced by a
generator
The current through two identical light bulbs connected in series is 0.25 A. The voltage across both bulbs is 110 V. The resistance of a single light bulb is
220 ohms
Two charges separated by 1 m exert a 1-N force on each other. If the charges are pulled to a
3-M separation distance, the force on each charge will be 0.11 N
The electrical force on a 2-C charge is 60 N. What is the value of the electric field at the place where the charge is located?
30 N/C
Two charges separated by 1 m exert a 1-N force on each other. If the magnitude of each charge is doubled, the force on each charge is
4 N
An electric heater is rated at 300 W when used in a 110-V circuit. The safety fuse in the circuit can handle 15 A of current. How many heaters can be safely operated in the circuit?
5
When a 10-V battery is connected to a resistor, 2 A of current flow in the resistor. What is the resistor's value?
5 ohms
A coulomb of charge that passes through a 6-V battery is given
6 joules
What is the power rating of a light bulb when 0.8 A flow through it when connected to a 120-V outlet?
96 W
Two charged particles repel each other will a force F. If the charge of one of the particles is doubled and the distance between them is also doubled, then the force will be
F/2
A balloon will stick to a wooden wall if the balloon is charged
either way
Which force binds atoms together to form molecules?
electrical force
A proton and an electron are placed in an electric field. Which undergoes the greater acceleration?
electron
A conductor differs from an insulator in that a conductor
none of these
What is the resistance of a 120-W incandescent lamp connected to a 120-V pow
none of these
A wire carrying a current is normally charged
not at all
Two charged particles held close to each other are released. As they move, the force on each particle increases. Therefore, the particles have
opposite signs
The headlights, radio, and defroster fan in an automobile are connected in
parallel with a switch for each
The number of electrons delivered daily to an average American home by an average power utility in the mid 1980s was
zero