What is the resistance of a hair dryer? What is the current in the hair dryer when it is used?
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
A battery is a voltage source, always providing the same potential difference regardless of the current. It is possible to make a current source that always provides the same current regardless of the potential difference. The circuit in FIGURE P28.56 is called a current divider. It sends a fraction of the source current to the load. Find an expression for in terms of and You can assume that the load’s resistance is much less than
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