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Chapter 23

Terms in this set (43)

Just as in hydraulic circuits there is water pressure, in electric circuits there is
voltage
To think of electric potential difference we are thinking about
voltage
Voltage is most similar to
pressure
A suitable electric pump in an electric circuit is a
both of these
It is correct to say that in electric circuits
all of the above
Unit of electric resistance
Ohm
If two copper wires of the same length have different thickness, then the thicker wire has
less resistance
If you stretch a copper wire so that it is thinner, the resistance between its ends
increases
When you turn on a lamp, the initial current in its filament is greater at first, rather than a moment later, which indicates
increased temperature means increased resistance.
Electric resistance in our skin is lowered when our skin is
moist
The voltage across a 10-ohm resistor carrying 5 A is
more than 20
The current in 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
Alternating current is normally produced by a
generator
A capacitor is useful in
smoothing pulsed current
For electric current in the home, your power company supplies
energy
The source of electrons that illuminate a common lamp in your home is
atoms in the lamp filament
Electrons that are energized to glow in the filament of a common ac lamp are
electrons already in the filament.
When Eddie Electron experiences an electrical shock, the source of electrons composing the shock is
Eddie's body
Electrons flow in an electric circuit by
Interacting with an established electric field
The electric field established by a generator in an ac circuit
changes magnitude and direction with time
In units of measurement, power in watts is equal to
amperes x volts
One kilowatt is a unit of
power
The electric power supplied to a lamp that carries 2 A at 120 V is
240 Watts
A 100-W lamp glows brighter than a 25-W lamp. The current drawn by the 100-W lamp is
greater
The energy dissipated in a light bulb in a circuit is provided by the
voltage source
A 60-W light bulb connected to a 120-V source draws a current of
0.5 A
A power line with a resistance of 2 ohms carries a current of 80 A. The power dissipated in the line is
12,800 W
The power dissipated in a 4-ohm resistor carrying 3 A is
36 W
The current drawn by a 1200-W toaster connected to 120 V is 10 A. The resistance of the toaster coils is
12 ohms
A heater draws 20A when connected to a 110-V line. If the electric power costs 20 cents per kilowatt hour, the cost of running the heater for 10 hours is
$4.40
A lamp rated 23W 120V means that it will deliver 23 W
when the voltage across it is 120 V.
The amount of current in an incandescent bulb rated 75W 120V is about
0.6 A
Compared with the amount of current in the filament of a lamp, the amount of current in the connecting wires is
The same
By convention, the direction of current in a circuit is
both of these
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
When a pair of identical lamps are connected in parallel
all of the above
Modern automobile headlights are connected in
parallel
The safety fuse in an electric circuit is connected to the circuit in
series
Something in the current in lamps is too feeble to produce glowing of the lamp filaments, which occurs when
Too many lamps are connected in series
As more lamps are connected in a parallel circuit, the overall current in the power source
increases
To connect a pair of resistors so their equivalent resistance (the single resistor having their combined value) will increase, connect them in
series
The equivalent resistance of any parallel branch in a circuit is
Always less than the resistance of the lowest resistor
When a pair of 1-ohm resistors are connected in series, their equivalent (combined) resistance is 2 ohms, and when connected in parallel is
1/2 ohm
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