Physics 8: HW3 book problems
All Problems from Chapter 10:
- E.2: You have an electrically neutral toy which you divide into two
pieces. You notice that at least one of those pieces has an electric
charge. Do the two pieces attract or repel each other, or neither?
- E.10: After you peel a sticker from its paper backing, the two attract
one another. Explain their attraction.
- E.32: The two prongs of a power cord are meant to carry current to and
from a lamp. If you were to plug only one of the prongs into an outlet,
the lamp wouldn't light at all. Why wouldn't it at least glow at half its
normal brightness?
- P.2: If you separate the two socks in Problem 1 until they're 5 cm
apart, what force will each sock exert on the other? [P.1: You remove two
socks from a hot dryer and find that they repel with forces of 0.001 N when
they're 1 cm apart. If they have equal charges, how much charge does each
sock have?]
- P.13: An automobile has a 12-W reading lamp in the ceiling. This lamp
operates with a voltage drop of 12 V across it. How much current flows
through the lamp?
- P.14: The rear defroster of your car operates on a current of 5 A. If
the voltage drop across it is 10 V, how much electric power is it consuming
as it melts the frost?
- P.15: Your portable FM radio uses two 1.5 batteries in a chain
(series). If the batteries send a current of 0.05 A through the radio, how
much power are they providing to the radio?
- P.18: How much power is the bulb of the first flashlight in Problem 17
consuming? How much power is the bulb of the second flashlight consuming?
[P.17: You have two flashlights that have 2-A currents flowing through
them. One flashlight has a single 1.5-V battery in its circuit, while the
second flashlight has three 1.5-V batteries connected in a chain (series)
that provides 4.5 V. How much power is the battery in the first flashlight
providing? How much power is each battery in the second flashlight
providing?]
- P.19: A 1.5-V alkaline D battery can provide about 40,000 J of electric
energy. If a current of 2 A flows through two D batteries while they're in
the circuit of a flashlight, how long will the batteries be able to provide
power to the flashlight?
- P.23: Each of the two wires in a particular 16-gauge extension cord has
an electric resistance of 0.04 Ω. You're using this extension cord
to operate a toaster oven, so a current of 15 A is flowing through it.
What is the voltage drop across each wire in the extension cord?
- P.24: How much power is wasted in each wire of the extension cord in
Problem 23? [TWM note: does it get warm?]
- P.25: The two wires of a high-voltage transmission line are carrying
600 A to and from a city. The voltage between those two wires is 400,000
V. How much power is the transmission line delivering to the city?
- P.27: How much current flows through a 100-Ω heating filament
when the voltage drop across it is 5 V?
- P.28: If you subject a 2500-Ω heating filament to a voltage drop
of 100 V, how much current will flow through it?
- P.30: The 2-A current flowing through a wire to a distant buzzer
experiences a 2-V voltage drop. What is the electrical resistance of that
wire?
- P.32: If a 1000-Ω heating filament is carrying a current of 0.120
A, what voltage drop is that current experiencing?