Electrical Theory
True or False:
Electric current is the movement of electrons from one atom to another.
False
measures pressure or force that pushes electric current forward through a conductor
Volt (V) or Voltage
A device uses 120 volts and 2 amps. How many watts does it use?
240 watts.
A 600-watt appliance runs on 120 volts. How many amps does it draw?
5 amps.
A device uses 240 watts and draws 2 amps. What is its voltage?
120 volts.
What is a conductor?
100 points each - Name three conductors.
Any material that conducts electricity
Example: metal, copper, and tap water
measures resistance of an electric current
ohm (O)
A 120-V appliance drawing 5 amps uses this many watts.
600 watts.
A 960-watt microwave runs on 120 volts. How many amps does it draw?
8 amps.
A device uses 180 watts and draws 3 amps. What is its voltage?
60 volts.
A material that does not transmit electricity
DOUBLE JEOPARDY! What's another for it?
Non-conductor
DOUBLE JEOPARDY! Insulator
measures how electric energy is being used.
Watt (W)
A device draws 10 amps from a 120-volt outlet. Calculate its power.
1,200 watts.
A 1,200-watt appliance runs on 120 volts. How many amps does it draw?
10 amps.
A machine uses 480 watts and draws 4 amps. What is its voltage?
120 volts.
Define the difference between AC and DC. (3)
DOUBLE JEOPARDY: Provide 3 examples of each.
Direct: constant, even flowing current, travels in one direction, and produced by chemical means [phones, flashlights, cordless handheld devices]
Alternating: rapid, interrupted current, flows in both directions, and produced by mechanical means [corded tools]
What is the term for 1,000 W?
Kilowatts
A 1,500-watt space heater runs on 120 volts. About how many amps does it draw?
12.5 amps
A 1,500-watt space heater runs on 120 volts. How many amps does it draw?
12.5 amps.
A circuit carries 6 amps and supplies 1,440 watts of power. What voltage is the circuit operating at?
240 volts.
What apparatus changes direct current to an alternating current?
DOUBLE JEOPARDY! What apparatus changes alternating current to direct current?
Inverter
DOUBLE JEOPARDY! Rectifier
measures strength/flow of an electric current
Amp (A)
A 15-A, 120-V circuit has a theoretical maximum electrical power of this many watts.
1800 watts.
Two 1,500-watt space heaters plugged into the same 120-V circuit draw a combined current of approximately this many amps.
What is 25 amps?
Two identical devices each use 960 watts and draw 4 amps. What voltage does each device require?
240 volts.