1a. define: Photon
a small “package” of light that acts like a particle
1b. define: charging by conduction
charging an object by allowing it to come into contact with an object that already has an electrical charge
1c. define: charging by induction
charging an object without direct contact between the object and a charge
1d. define: electrical current
the about of charge that travels past a fixed point in an electric circuit each second
1e. define: conventional current
Current that flows form the positive side of the battery to the negative side. This is the way current is drawn in circuit diagrams, even though it is wrong
1f. define: resistance
the ability of a material to impede the flow of charge
1g. define: open circut
A circuit that does not have a complete connection between the two sides of the power source. As a result, current does not flow.
- look in book on page 311, #2
look in book
- The force between the south pole of a magnet and the north pole of another magnet is measured. If the distance between the poles is increased by a factor of 3, how does the new force compare to the old one? Is the force attractive or repulsive?
the force is divided by 9; it is an attractive force
- Two charged particles are placed 10 centimeters from each other and the resulting force is measured. The charge on object #1 is then doubled and the charge on object #2 is left the same. Also, the distance between the objects is reduced to 5 centimeters. How does the new force compare to hte old force?
the new force is 8 times stronger than the old one
- What causes the electromagnetic force?
the exchange of photons causes the electromagnetic force
- Given your answer to question #5, why don’t charged particles glow?
charged particles do not glow because the photons they emit are not visible to you and me
- If you were to use a positively charged rod to charge an object by induction, what charge will the object have?
the object will be negatively charged
- If you were ti use a positively charged rod to charge an object by conduction, what charge will the object have?
the object will be positively charged
- An electrical circuit uses a large voltage but a small current. Is the energy of each electron high or low? Are there many electrons flowing through the circuit, or are there few? Is the circuit dangerous?
each electron has high energy; few electrons flow through the circuit; the circuit could be dangerous
- Under what conditions is an electrical current reasonably safe?
a circuit is reasonably safe when both the voltage and the current are low
- look in book on page 312, #11
look in book
- look in book on page 312, #12
conventional current assumes that electricity is the flow of positive charges
- You have two wires. One is long and the other is short. Other than that, they are identical. Which has more resistance?
the longer wire has more resistance
- You have two wires. One is thin and the other is thick. When the same current is run through each wire, which will get hotter?
the thin wire will get hotter
- look in book on page 312, #15
in circuit (b), the light bulb glows
- Three lights are in a circuit. When one burns out, they all go out. When the burnt-out one is replaced with a good light, the other two lights work again. Are the lights wired in a parallel circuit or a sires circuit?
the bulbs are wired in a series circuit
- If it takes a flow of charged particles to make a magnet, where is hte charged particle flow in a permanent magnet?
in a permanent magnet, the flow of charged particles is the motion of the electrons in its atoms
- Is it possible to have a permanent magnet with only a north pole?
this is not possible
