I.P.C

What is electric current?

continuous flow of electrons through a material

What is electric current measured in?

amperes (amps) (A)

1 amp \=

one coulomb of charge (approximately 6.24 x 1018 electrons) per second

What is direct current (DC)? What is it used for?

when a charge flows in one direction only, most devices that use batteries such as a flashlight run on direct current

What is alternating current (AC)? What is it used for?

when a charge regularly reverses its direction of flow, most buildings are wired using AC because it is more economical & safe

What are conductors? Examples?

materials in which a charge can easily pass through, metals such as copper, silver, and gold

What kind of structure do metals have and what does it do?

"lattice" atomic structure which allows electrons to freely move and each atom has at least one free electron

What are electrical insulators? Why are they important for safety? Examples?

materials in which a charge does not easily flow electrical wires are coated with plastic and/or rubber for safety and to prevent contact with other conductors rubber, plastic and wood

What is an electrical load? Examples?

any component of a circuit that consumes power or energy. Bulbs, resistance devices, motors, and refrigerators

What is electrical resistance? Why is it an issue when transporting electrical charges?

ability of a material to block or "resist" an electric flow of charges energy is lost to heat by friction

What does the resistance of a material depend on?

thickness, length and temperature

What lowers the resistance?

lower temperatures, shorter length and greater thickness

What are the units for resistance? Symbol?

Ohms (Ω)

What are superconductors? What degree do they have to be cooled to to function?

materials that allow an electric charge to flow with little or no resistance

\-135 C (-211 F)

What is the common name for potential difference and what is it measured in? Symbol?

voltage, volts (V)

What is voltage? Examples?

difference in the amount of energy that charge carriers have between two points in a circuit battery

Which way do the electrons flow?

from negative to positive

What did George Ohm discover?

Ohm figured out that voltage (V) in a circuit equals the product of the current (I) and resistance (R)

What is directly proportional to current and resistance? Example?

voltage, voltage will increase if the current or resistance increases and voltage will decrease if the current or resistance decreases

\_________ and \______ are inversely proportional to each other. Example?

resistance, current

increasing one of them will decrease the other

What is the use of the ammeter? Resistance? Connection?

measures current, low, in series

What is the use of the voltmeter? Resistance? Connection?

measures voltage between any 2 points in circuit, high, in parallel

What is an electrical motor?

electrical machine that converts electrical energy into mechanical energy.

What is a series circuit?

all of the current flows through each part of the circuit

What is a parallel circuit?

current is divided into separate paths

What is the function of a rheostat?

changes the resistance by sliding a contact up and down a coil, the more coiled wire that becomes part of the circuit, the greater the resistance

Does voltage remain the same in each part of a parallel circuit?

yes, voltage remains the same

What is the total current in a parallel circuit equal to?

sum of the current through each separate pathway

What is the voltage, current, resistance, and features of a series circuit?

add up voltage, current is equal, add up resistance, if one component burns, the others become inactive

What is the voltage, current, resistance, and features of a parallel circuit

voltage is equal, add up current, add up 1/R, if one component burns, current discontinues its flow only through that branch of the circuit

If the switch is closed then the current will flow but what happens to the brightness of one of the bulbs if the other one burns out?

other bulb will blow because no current is flowing

What happens to the brightness of the other bulbs if one of the bulbs burns out?

brightness of the other bulbs will remain the same because the voltage is the same for each branch of the circuit therefore the current will be unchanged for each individual branch of the circuit

How do you calculate voltage in a series circuit?

V1 + V2 + V3 \= total voltage

How do you calculate voltage in a parallel circuit?

V1 + V2 + V3 \= total voltage

How do you calculate current in a series circuit?

I1 \= I2 \= I3 \= total current

How do you calculate current in a parallel circuit?

!1 + I2 + I3 \= total current

How do you calculate resistance in a series circuit?

R1 + R2 + R3 \= total resistance

How do you calculate resistance in a parallel circuit?

1/R1 + 1/R2 + 1/R3 \= total resistance