Q. 7

Expert-verified
Found in: Page 790

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# What is the resistance of a hair dryer? What is the current in the hair dryer when it is used?

and .

See the step by step solution

## Step 1: Given information

We have given that .

We need to find the resistance of a hair dryer and the current in the hair dryer when it is used.

## Step 2: Simplify

When the current flows through a resistor, the energy is dissipated, the rate of the dissipated energy is the power. This rate where the energy is transferred from the current to the resistor is

From Ohm's law , we can get an alternative formula

The formula shows the largest dissipated power if we have several resistors. Solve equation (2) for which is our target to be in the form

Now, putting the values of and into equation (3) to get by

## Step 3: Simplify

For the current, solving equation (1) to be in the form

Now we plug the values for and into equation (4) to get by