Power Loss of a Circuit on a Contractor's Exam

As either AC or DC goes through a circuit, power is lost.

This power can be thought of as being "lost", but recall that it is simply being corrected to heat. This power loss is experienced as watts and is calculated by the following formula:

W = I2 x R

Example: What is the power loss of a 2.1A circuit where the resistance is 69 Ω?

W = (2.1)2 A x 69 Ω
W = 4.41 A x 69 Ω
W = 304.29 watts

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