Chapter 2.2, Problem 14E

Ohm’s Law: says that when electric current is flowing across a resistor, the current i, measured in amperes, can be calculated from the voltage v, measured in volts, and the resistance R, measured in ohms. The relationship is given by

$i=\frac{v}{R}\text{amperes}$.

a. A resistor in a radio circuit is rated at 4000 ohms.

i. Find a formula for the current as a function of the voltage.

ii. Plot the graph of i versus v. include values of the voltage up to 12 volts.

iii. What happens to the current when the voltage increases?

b. The lights on your car operate on a 12-volt battery.

i. Find a formula for the current in your car lights as a function of the resistance.

ii. Plot the graph of i versus R. We suggest a horizontal span here of 1 to 25.

iii. What happens to the current when the resistance increases?