Q. 7

Expert-verifiedFound in: Page 790

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 .

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.

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

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

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

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