5. You are measuring the current in a circuit that is operated on an 18 V battery. The ammeter reads 40 mA. Later you notice the current has dropped to 20 mA. How much has the voltage changed?
9. Two resistors are in series: a 5.6 kΩ resistor and a 4.7 kΩ resistor. The voltage drop across the 5.6 kΩ resistor is 10 V. The voltage across the 4.7 kΩ resistor is