Section 4 Flashcards
The force that binds atoms together to form molecules is
electrical.
The fundamental force underlying all chemical reactions is
electrical.
A fundamental rule of electricity is that: a) like kinds of charges repel; b) unlike kinds of charges attract; c) both of these; d) neither of these.
c) both of these.
An electron and a proton: a) attract each other; b) repel each other; c) neither attract nor repel each other.
a) attract each other.
In an electrically neutral atom the number of protons in the nucleus is equal to the number of
electrons that surround the nucleus.
Which of these does NOT have an electrical charge: a) proton; b) electron; c) neutron.
c) neutron.
It is said that electric charge is quantized, which means that the charge on an object: a) may occur in an infinite variety of quantities; b) is a whole-number multiple of the charge on one electron; c) will interact with neighboring electric charges; d) can be neither created nor destroyed; e) is sometimes positive.
b) is a whole-number multiple of the charge on one electron.
To say that electric charge is conserved means that no case has ever been found where
net charge has been created or destroyed.
To become a negative ion, an atom must
gain an electron.
If electrons are stripped from an atom it becomes a
positive ion.
A main difference between gravitational and electric forces is that electrical forces: a) attract; b) repel or attract; c) obey the inverse-square law; d) act over shorter distances; e) are weaker.
b) repel or attract.
The force between two charged particles depends: a) only on the amount of charge on the two particles; b) on the total charge and gravity; c) only on the distance between the particles; d) on the charge on the quarks; e) on the amount of charge on the two particles and their distance from each other.
e) on the amount of charge on the two particles and their distance from each other.
According to Coulomb’s law, a pair of particles that are placed twice as far apart will experience forces that are: a) half as strong; b) one-quarter as strong; c) twice as strong; d) 4 times as strong.
b) one-quarter as strong.
__________ is when you bring a charged object near another object and cause a movement of charge.
Induction
Conducting materials are composed of atoms with
loose outer electrons.
When a material has no electrical resistance it is
a superconductor.
Electrons can be transferred from one place to another by the process of: a) friction; b) contact, which means touching; c) induction, which means non-touching; d) all of the above; e) none of the above.
d) all of the above.
If you comb your hair and the comb becomes negatively charged, then your hair becomes
positively charged.
The unit of electrical resistance is the
ohm.
Heat a copper wire and its electric resistance
increases.
If two copper wires of the same length have different thickness, then the thicker wire has
less resistance.
Ohm’s law tells us that the amount of current produced in a circuit is: a) directly proportional to voltage; b) inversely proportional to resistance; c) both of these; d) neither of these.
c) both of these.
When you double the voltage in a simple electric circuit, you double the
current.
The voltage across a 10-ohm resistor carrying 5 A is: a) 5 V; b) 10 V; c) 15 V; d) 20 V; e) more than 20 V.
e) more than 20 V.
The current through a 10-ohm resistor connected to a 120-V power supply is: a) 1 A; b) 10 A; c) 12 A; d) 120 A.
c) 12 A.
The electric power of a lamp that carries 2 A at 120 V is: a) 1/6 watts; b) 2 watts; c) 60 watts; d) 20 watts; e) 240 watts.
e) 240 watts.
If an electric toaster rated at 110 V is accidentally plugged into a 220-V outlet, the current drawn by the toaster will be
twice its normal value.
A 100-Watt incandescent lamp glows brighter than a 25-Watt lamp. The electrical resistance of the 100-Watt lamp must be
less.
In an ac circuit, the electric field: a) increases via the inverse-square law; b) changes magnitude and direction with time; c) is the same everywhere; d) none of these.
b) changes magnitude and direction with time.
On some early automobiles both headlights went out when one bulb burned out. The headlights must have been connected in
series.
Modern automobile headlights are connected in
parallel.
A circuit breaker often serves the same purpose as a
fuse.
The source of energy that illuminates a lamp in your home is: a) the power company; b) the electrical outlet c) atoms in the bulb filament; d) the wire leads to the lamp; e) the source voltage.
a) the power company.
Electrons that are energized to glow in the filament of a common ac lamp are: a) supplied by a wall outlet; b) supplied by a wall outlet, which in turn are supplied by your power company; c) electrons are already in the filament; d) none of the above.
c) electrons are already in the filament.
Electric power is the rate at which electric energy is converted into another form, in equation form is
current multiplied by voltage
The power consumed by a device drawing 0.8 A when connected to 120 V is
96 W
Consider a lamp powered by a battery. Charge flows
through both the battery and the lamp.
When two lamps are connected in series to a battery, the electrical resistance that the battery senses is: a) more than the resistance of either lamp; b) less than the resistance of either lamp; c) none of these.
a) more than the resistance of either lamp.
When two lamps are connected in parallel to a battery, the electrical resistance that the battery senses is: a) more than the resistance of either lamp; b) less than the resistance of either lamp; c) none of these.
b) less than the resistance of either lamp.
When a pair of 1-ohm resistors are connected in series, their equivalent (combined) resistance is 2 ohms, and when connected in parallel is: a) 1/2 ohm; b) none of the above; c) also 2 ohms.
a) 1/2 ohm
The source of all magnetism is
moving electric charge.
The force that acts between a pair of magnetic poles depends on: a) magnetic pole strength; b) separation distance; c) both of these; d) neither of these.
c) both of these.
Like kinds of magnetic poles repel while unlike kinds of magnetic poles
attract.
A weak and strong magnet repel each other. The greater repelling force is by the: a) stronger magnet; b) weaker magnet; c) both the same; d) none of the above.
c) both the same.
Whereas electric charges can be isolated, magnetic poles
cannot.
If you break a bar magnet in half you’ll: a) destroy its magnetic properties; b) have two magnets; c) have two and a half magnets; d) none of the above.
b) have two magnets.
Where magnetic field lines are more dense, the field there is
stronger.
An electromagnet can be made stronger by: a) increasing the number of turns of wire; b) increasing the current in a coil; c) both a. and c.; d) none of the above.
c) both a. and c.
Several paper clips dangle from the north pole of a magnet. The induced pole in the bottom of the lowermost paper clip is a
north pole.
Magnetic compasses apparently were first used by
pigeons, then Chinese.
