physics chapter 34 and 35

when plugged into a 120-V wall outlet, how much current is used by a toaster rated at 1200 W?

10 A

the current through a 10-ohm resistor connected to a 120-V power supply is___

12 a

power outlets in our homes typically have a potential difference of____

120 V

how much power is used by a 6.0-V flashlight battery that draws .5A of current?

3 W

an electric heater is rated at 300 W for use in a 110-V circuit. The safety fuse in the circuit can handle 15A of current. How many heaters can be safely operated in the circuit?

5

when a 10-v battery is connected to a resistor, 2 A of current flows in the resistor. What is the resistor's value?

5 ohms

a 10-ohm resistor has a 5-a current in it. what is the voltage across the resistor?

50 or 15

the frequency of AC current in North america is___

60 hertz

a light bulb is plugged into a 120- volt outlet and has an .8 A current in it. what is the power rating of the light bulb?

96 W

current from a battery is always____?

DC

when one light bulb in a series circuit containing several high bulbs burns out_____

all of the other light bulbs go out

in order to form an electrical circuit, you ned to have____

all the above: a power source, a light bulb or some resistance, wires or conductors to connect everything, a complete path for the current

electrical resistance in a wire depends on the wire's ____

all the above: conductivity, length, thickness, temperature

an example of a voltage source is____

all the above: dry cell, flashlight battery, car battery, and a generator

fuses and circuit breakers are used to _____

all the above: protect us, prevent overloading, break the circuit when too much current is being used, and keep wires from getting overheated

closed circuit is a circuit in which____

charge can flow

electric power is defined as____

current times voltage

when we say an appliance such as a toaster uses up electricity, we really are saying that____

electron kinetic energy is changed into heat

compared to the filament thickness on a 60-w light bulb, the filament thickness of a 100-w light bulb will be___

greater

an open in a series circuit

happens for all the above

for most conductor, as their temp increases, their resistance ____

increases

what is the purpose of the third prong in an appliance plug?

it prevents charge from building on an appliance by grounding it

when resistors are put in series next to each other, the total resistance is____

larger than that of any individual resistor

compared to thin wires, electrical resistance in thick wires is____

less

compared to the resistance of two resistors connected in series, the same two resistors connected in parallel have____

less resistance

it was discovered that the current to a circuit is directly proportional to the voltage and inversely proportional to the resistance. This is____

ohm's law

electrical resistance is measured in____

ohms

electrical elements in our homes are connected in____

parallel

in an alternating current circuit, electrons flow is___

simply back and forth

when resistors are put in parallel with each other their total resistance is _____

smaller than the resistance of any one of the resistors

where do the electrons come from that produce heat and light in a light bulb?

the bulbs wire filament

electric current is____

the flow of electric charge

when one light bulb in a parallel circuit containing several light bulbs burns out, ____

the other bulb continues burning

when a light switch in a DC circuit is turned on, the average net speed of electrons in the lamp is____

the speed of sound waves in metal

the primary reason a bird can perch harmlessly on bare high voltage wires is that____

there is no potential difference across the bird's feet

if u plug an electric toaster rated at 110 V into a 220- V outlet, current in the toaster will be _____

twice what it should be

an ampere is a____

unit of current

in a simple parallel circuit____

voltage across each branch is always the same

a short circuit occurs when?

wires in a circuit touch by passing circuit components

the symbol used to represent resistance in a schematic diagram is____

zigzag line