1. An ammeter registers 2.5 A of current in a wire that is connected to a 9.0 V battery. What is the wire's resistance?
2. A small electronic device is rated at 0.25 W when connected to 120 V. What is the resistance of this device?
Current (I) = 2.5 A
Potential difference (V) = 9.0 V
Resistance (R) = ...
Ohm's law: V = I*R