Answer Key: Ohm's Law Exercise 2

1. Suppose that the dc generator in Figure 1 produces 10 V and the potentiometer is set to a value of 10 ohms. What is the current?
1 A

2. Imagine that dc generator in Figure 1 produces 100 V and the potentiometer is set to 10 kiloohms. What is the current?
10 mA

3. Suppose that dc generator in Figure 1 is set to provide 88.5 V, and the potentiometer is set to 477 Megaohms. What is the current?
0.186 uA

4. Suppose the potentiometer in Figure 1 is set to 100 ohms, and the measured current is 10 mA. What is the dc voltage?
1 V

5. Adjust the potentiometer in Figure 1 to a value of 157 kiloohms, and suppose the current reading is 17.0 mA. What is the voltage of the source?
2.67 KV

6. Suppose you set the potentiometer in Figure 1 so that the meter reads 1.445 A, and you observe that the potentiometer scale shows 99 ohms. What is the voltage?
143.055 V

7. If the voltmeter in Figure 1 reads 24 V and the ammeter shows 3.0 A, what is the resistance of the potentiometer?
8 ohms

8. What is the value of the resistance in Figure 1 if the current is 18 mA and the voltage is 229 mV?
13 ohms

9. Suppose the ammeter in Figure 1 reads 52 uA and the voltmeter indicates 2.33 kV. What is the resistance?
45 Megaohms

10. Suppose that the voltmeter in Figure 1 reads 12 V and the ammeter shows 50 mA. What is the power dissipated by the potentiometer?
0.60 W

11. If the resistance in the circuit of Figure 1 is 999 ohms and the voltage source delivers 3 V, what is the power dissipated by the potentiometer?
9 mW

12. Suppose the resistance in Figure 1 is 47 kiloohms and the current is 680 mA. What is the power dissipated by the potentiometer?
22 kW

13. How much voltage would be necessary to drive 680 mA through a resistance of 47 kiloohms?
32 kV

14. Consider five resistors in parallel. Call them R1 through R5. Let the resistance values be as follows: R1 = 100 ohms, R2 = 200 ohms, R3 = 300 ohms, R4 = 400 ohms, and R5 = 500 ohms. What is the total resistance?
43.8 ohms

15. cont.... What is the total conductance?
0.02283 S or Mho




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