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PLEASE HELP

A hair dryer has a resistance of 11.5 Ω at 120 V.

What is the approximate power rating of the hair dryer?

1,250 W
1,380 W
15,900 W
167,000 W

2 Answers

6 votes

Answer:

1250

Step-by-step explanation:

just took the test

User Bigchao
by
8.1k points
5 votes
The answer is 1,250 W.
Solution:
To use the power rule P = VI, we need to know both the current I flowing through the resistor, and the voltage V across the resistor. But by substituting Ohm’s law I = V/R, we can also express the power rule equation P = VI as
P = R (V/R)^2 = R V^2 / R^2 = V^2 / R
We can now substitute the values for the resistance and voltage into the equation to get the power rating:
P=V^2 / R = (120)^2 / 11.5 = 1252.17 Watts ≈ 1250 Watts
User Custom
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7.8k points