chat 34-35
A closed circuit is a circuit in which carge A can flow B is prevented from flowing
A
A short circuit occurs when A a wire is placed around an electrical component B very short wires are used in the circuit C current lasts in the circuit for only a short time D all of the above
A
A wire carrying a current is normally charged A not at all B positively C negatively
A
Compared to the resistance of two resistors connected in series, the same two resistors connected in parallel have A less resistance B more resistance C the same resistance
A
Compared to thin wires, electrical resistance in thick wires is A less B the same C greater
A
Current from a generator is always A AC B DC
A
Electric power is defined as A current times voltage B current divided by voltage C current times resistance D ressitance times voltage E voltage divided by current
A
How quickly charge flows through a circuit is A current B voltage C resistance D power
A
The net drift speed of electrons in a wire is about A 0.01 cm/s B 10 m/s C 100 km/h D a few million km/h E the speed of light
A
When resistors are put in parallel with each other their overall resistance is A smaller than the resistance of any of the resistors B larger than the resistance of any other resistor C the same as the resistance of the smallest resistor D the same as the resistance of the largest resistor
A
n 2015, the number of electrons delivered to an average American home by an average power utility was A zero B 110 C 220 D billions of billions E none of the above
A
A 60-W light bulb and a 100-W light bulb are each connected to a 120-V outlet. Which light bulb has more current in it? A the 60-W bulb B the 100-W bulb C the same amount of current flows in both
B
For most conductors, as their temperature increases, their resistance A decreases B increases C stays the same
B
In solid conductors, electric current is the flow of A positive and negative charges B electrons C negative ions D protons E none of the above
B
The total resistance of two 6-ohm resistors in parallel is A 0 ohms B 3 ohms C 6 ohms D 12 ohms E 36 ohms
B
To convert AC to DC, which components are essential? A resistor and switch B diode and capacitor C bulb and capacitor D diode and resistor
B
Two bulbs, one with high resistance and one with low resistance, are connected in parallel to a battery. The current is larger in the bulb with A high resistance B low resistance C current is the same in both
B
Two electric deviced are connected in series. The total resistance to current in the circuit is A zero B the sum of the individual resistances along the circuit path C the difference between the individual resistances along the circuit path D the product of the individual resistances along the circuit path
B
What is the resistance of a toaster that uses 5 A of current when connected to a 120-V power supply? A 5 ohms B 24 ohms C 120 ohms D 600 ohms E none of the above
B
Which of the following contains a bi-metallic strip that opens a circuit when too hot? A capacitor B circuit breaker C fuse D diode E short circuit
B
Which of the following is a device used to either cut off or allow electrons to flow in a circuit? A battery B switch C resistor D connecting wire
B
Who was the inventor of alternating current? A Edison B Tesla C Franklin
B
A 6 volt battery is connected to a bulb with 2 ohms of resistance. What is the power used by the bulb? A 3 W B 12 W C 18 W D 24 W
C
A heater uses 21 A when connected to a 110-V line. If electric power costs 10 cents per kw-h in this location, the cost of running the heater for 13 hours is A $0.30 B $0.75 C $3.00 D $7.51 E none of the above
C
A light bulb is plugged into a 120-V outlet and has a 0.7 A current in it. What is the power rating of the light bulb? A 12 W B 17 W C 84 W D 120 W E 171 W
C
As more lamps are put into series, the overall current in the circuit A stays the same B increases C decreases
C
The current through a 5-ohm resistor connected to a 150-V power supply is A 1 A B 10 A C 30 A D 150 A E none of the above
C
The current through two identical light bulbs connected in series is 0.25 A. The total voltage across both bulbs is 120 V. The resistance of a single bulb is A 24 ohms B 48 ohms C 240 ohms D 480 ohms E none of the above
C
The energy source of a circuit is the A current B resistance C voltage D drift speed
C
The primary reason a bird can perch harmlessly on bare high voltage wires is that A the current through the wire is low B a bird has a low electrical resistance C there is no potential difference across the bird's feet D the bird is grounded
C
Two lamps, one with high resistance and one with low resistance, are connected in series. The current is greater in the lamp with A high resistance B low resistance C current is the same in each
C
Wet skin is dangerous around electricity because it A acts like a capacitor B increases voltage C reduces your resistance D grounds you E acts as a short circuit
C
When one light bulb in a parallel circuit containing several light bulbs burns out, the other light bulbs A do not burn at all B burn brighter C burn the same as before
C
A material with almost zero resistance is called a A semiconductor B diode C capacitor D superconductor
D
A woman experiences an electric shock. The electrons making the shock come from A the ground B the electric field in the air C a nearby power supply D the woman's body E the object causing the shock
D
Electrical resistance in a wire depends on the wire's A thickness B conductivity C length D all of the above E none of the above
D
In a simple parallel circuit A voltage across each branch is the same B the current through each resistor is inversely proportional to the resistance C current is split at each junction to a branch D all of the above E none of the above
D
The total resistance of a 6-ohm and 6-ohm resistor in series is A 0 ohms B 3 ohms C 6 ohms D 12 ohms E 36 ohms
D
When plugged into a 120-V outlet, how much current is used by an electric blanket rated at 140 W? A 16,800 A B 140 A C 120 A D 1.2 A E none of the above
D
Which of the following is "Ohm's Law"? A like charges repel; opposites attract B P=IV C F=kqq/d² D V=IR
D
Electric power is measured in kilowatt-hours T True F False
F
Most of the electricity we buy through power companies is direct current. T True F False
F
When connected in series, an electric circuit provides branched paths for the flow of electrons. T True F False
F
Unit for the amount of energy we buy from the power plant
Kilowatt-hour
When resistors are arranged in parallel, their overall resistance is less than that of the smallest resistor. T True F False
T
Type of current produced by generators
alternating current
Unit for current
amp
A closed path for charge to flow
circuit
Type of current produced by batteries
direct current
In order to form an electric circuit, you need to have A wires or conductors to connect everything B a power source C a light bulb or some resistance D a complete path for the current E all of the above
e
Providing a path for excess charge to flow, thereby neutralizing a charged object
grounding
Unit for resistance
ohm
The rate at which energy is used or dissipated
power
Circuit in which there is only one path for charge to flow
series
Unit for electric power
watt