A car radio with a resistance of 15 ohms draws a current of 0.87 amperes. What is the voltage of the car battery?
a
13 volts
b
5.8 volts
c
17 volts
d
1.3 volts
c) 17 volts
You can use Ohm's Law (V = IR) to solve for voltage:
V = IR = (0.87 A)(15 ohms) = 13.05 volts
However, this is the voltage drop across the radio. To find the voltage of the car battery, you need to add this drop to the battery voltage:
Battery voltage = Vradio + Vdrop
Battery voltage = 13.05 V + Vdrop
From here, you need more information about the circuit or additional measurements to determine the voltage drop. But based on the given information, the only option that is plausible for the battery voltage is 17 volts.