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REGENTS PHYSICS
STUDENT NOTES-ELECTRICITY AND MAGNETISM
ELECTRICAL POWER AND MAGNETISM
What is Power? Look back at your notes on mechanics.
ELECTRICAL POWER – is the product of potential difference (voltage) and current.
P = VI
Reference Tables
P = Power
V = Voltage
I = Current
…. Let’s look at the UNITS for the above equation.
(1 Volt)(1 Ampere) = ( 1 Joule/Coulomb) ( 1 Coulomb/Second)
= 1 Joule/Second
=
1 Watt
P = VI = (IR)I = I2R
Reference Tables
Example: A potential difference of 80.0 volts is applied across a 10
ohm resistor. What is the power dissipated in the resistor?
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FORMULA FOR ELECTRICAL ENERGY
W = Pt = VIt = I2Rt = V2t
R
Reference Tables
Electrical Energy is measured in ________________ .
Example: A current of 0.4 ampere is measured in a 150 ohm resistor. How much energy is
expended by the resistor in 30 seconds?
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