Ch 10-11
Two charges separated by one meter exert 1-N forces on each other. If the charges are pulled to 3-m separation distance, the force on each charge will be
0.11N
The current through a 10-ohm resistor connected to a 120-V power supply is
12A
Two charges separated by one meter exert 1-N forces on each other. If the magnitude of each charge is doubled, the force on each charge is
4N
A 10-ohm resistor has a 5-A current in it. What is the voltage across the resistor?
50-V
A circuit breaker serves the same purpose as
A fuse
When there is a change in the magnetic field in a closed loop of wire
All of these: a current is created in the loop of wire, a voltage is induced in the wire, and electromagnetic induction occurs.
If we think of the Earth as a magnet, its north (-seeking) pole is nearest
Australia.
Electric potential, measured in volts, is the ratio of electric energy to amount of electric
Charge
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
As more lamps are put into a parallel circuit, the overall current in the power source
Increases
On some early automobiles both headlights went out when one bulb burned out. The headlights must have been connected in
Series
In a common dc circuit, electrons move at speeds of
a fraction of a centimeter per second
The unit of electric charge, the coulomb, is the charge on
a specific large number of electrons
The principal advantage of ac power over dc power is that
ac voltage can be transformed via conventional transformers.
Rapid change of a magnetic field induces
an electric field
If a steady magnetic field exerts a force on a moving charge, that force is directed
at right angles to the direction of the motion.
Like kinds of magnetic poles repel while unlike kinds of magnetic poles
attract
Moving electric charges will interact with
both of these: an electric field and a magnetic field
Surrounding every moving electron is
both of these: an electric field and a magnetic field.
Thrust a magnet into a coil of wire and the coil
both of these: has a current in it and becomes an electromagnet.
The electrical force between charges depends on the
both of these: magnitude of electric charges and separation distance between electric charges
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
To say that electric charge is conserved is to say that electric charge
can be neither created nor destroyed
The electrical force between charges is strongest when the charges are
close together.
The primary purpose of a lightning rod is to
discharge the structure to which it is attached
Superconducting electromagnets
exist now
Magnetic domains normally occur in
iron
An electron is shot from the right, toward a spot just between the ends of the magnet. The electron
is deflected
To say that an object is electrically polarized is to say
its charges have been rearranged
Compared to the primary voltage, the secondary voltage may be
larger, smaller, or the same
If you comb your hair and the comb becomes positively charged, then your hair becomes
negatively charged.
Rub electrons from your hair with a comb and the comb becomes
negatively charged.
To say that electric charge is conserved means that no case has ever been found where
net charge has been created or destroyed.
Which pole of a compass needle points to a south pole of a magnet?
north pole
A main difference between gravitational and electric forces is that electrical forces
repel or attract
When a magnet is thrust into a coil of wire, the coil tends to
repel the magnet as it enters
Two protons attract each other gravitationally and repel each other electrically. By far the greater is
the electrical repulsion
Two lamps, one with a thick filament and one with a thin filament of the same material, are connected in series to a battery. The voltage is greater across the lamp with the
thin filament.