Question

Помогите пожалуйста 4. Complete these sentences using while. Follow the model. Model: The ammeter is used to measure the value of current.... The ammeter is used to measure the value of current while the ohmmeter is used to measure the value of resistance. 1. The ohmmeter is used to measure the value of resistance........... 2. The ammeter is connected in series... 3. When the ammeter is used to measure the value of current the circuit should be opened 5. Pair work. Put these questions to your groupmate. Let him/her answer them. 1.What is the ammeter used for? 2. What is the voltmeter used for? 3. What is the ohmmeter used for? 4. What terminals does a meter have? 5. Should the measured circuit be opened when the voltmeter is used? 6. Should the measured circuit be opened when the ammeter is used? 7. In what way should the voltmeter be connected to the circuit? 8. In what way should the ammeter be connected to the circuit? 9. What is the difference between a voltmeter and an ammeter? 10. What common meters are used to measure the values in a circuit? 6. Solve the following problems: 1. Suppose the ammeter scale reads 1.9 amp, the voltmeter scale reads 2.4 V; how much is the value of resistance in the measured circuit? 2. Suppose the ohmmeter scale reads 75 ohms, the voltmeter scale reads 220 V; how much is the value of current in the measured circuit? 3. Suppose that you have a series circuit consisting of three resistors and a voltage source. R1 = 0.18 ohm, R2= 1.15 ohms, R3 = 2 ohms, I=10 amp. Find the voltage drop across each resistor; find the value of voltage in the circuit. Suppose R1 gets open. What does it result in? 4. Two resistors are connected in series. Ri = 7,000, R2= 2,200, I = 110 amp. Find the voltage drop across each resistor. Suppose no current passes through the circuit, what does it result from?

Answer 1

1. The ohmmeter is used to measure the value of resistance while it is connected in paralltl to the resistor.

2. The ammeter is connected in series while the current is being measured.

3. While the value of current in the circuit is measured, the ammeter should be connected in series.

1. Suppose the ammeter scale reads 1.9 amp, the voltmeter scale reads 2.4 V; how much is the value of resistance in the measured circuit?

R = U / I = 2.4 / 1.9 = 1.26 Ohm

2. Suppose the ohmmeter scale reads 75 ohms, the voltmeter scale reads 220 V; how much is the value of current in the measured circuit?

I = U / R = 220 / 75 = 2.9 A

3. Suppose that you have a series circuit consisting of three resistors and a voltage source. R1 = 0.18 ohm, R2= 1.15 ohms, R3 = 2 ohms, I=10 amp. Find the voltage drop across each resistor; find the value of voltage in the circuit.

U1 = R1 * I = 0.18 * 10 = 1.8 V  

U2 = R2 * I = 1.15 * 10 = 11.5 V

U3 = R3 * I = 2 * 10 = 20 V

Suppose R1 gets open. What does it result in? I = 0

4. Two resistors are connected in series. R1 = 7,000, R2= 2,200, I = 110 amp. Find the voltage drop across each resistor.

U1 = R1 * I = 7,000 * 110 = 770,000 V  

U2 = R2 * I = 2,200 * 110 = 242,000 V

Suppose no current passes through the circuit, what does it result from?

It results from the broken circuit.

Answer 2

1. The ohmmeter is used to measure the value of resistance while applying a small known current through the circuit.

2. The ammeter is connected in series to the circuit element whose current is being measured.

3. When the ammeter is used to measure the value of current, the circuit should be closed.

4. Pair work:

5. What is the ammeter used for? Answer: The ammeter is used to measure the value of current in a circuit.

6. What is the voltmeter used for? Answer: The voltmeter is used to measure the potential difference between two points in a circuit.

7. What is the ohmmeter used for? Answer: The ohmmeter is used to measure the value of resistance in a circuit.

8. What terminals does a meter have? Answer: A meter usually has two terminals, one for the positive and one for the negative connection.

9. Should the measured circuit be opened when the voltmeter is used? Answer: No, the measured circuit should not be opened when the voltmeter is used. Instead, the voltmeter should be connected in parallel to the circuit element whose potential difference is being measured.

10. Should the measured circuit be opened when the ammeter is used? Answer: No, the measured circuit should not be opened when the ammeter is used. Instead, the ammeter should be connected in series to the circuit element whose current is being measured.

11. In what way should the voltmeter be connected to the circuit? Answer: The voltmeter should be connected in parallel to the circuit element whose potential difference is being measured.

12. In what way should the ammeter be connected to the circuit? Answer: The ammeter should be connected in series to the circuit element whose current is being measured.

13. What is the difference between a voltmeter and an ammeter? Answer: The main difference between a voltmeter and an ammeter is that a voltmeter measures potential difference while an ammeter measures current flow.

14. What common meters are used to measure the values in a circuit? Answer: The common meters used to measure values in a circuit are ammeter, voltmeter, and ohmmeter.

15. Problem-solving:

16. To calculate the value of resistance, we can use Ohm's law, which states that resistance equals the potential difference divided by the current. So, R = V/I = 2.4/1.9 = 1.26 ohms.

17. To calculate the value of current, we can use Ohm's law again, which states that current equals the potential difference divided by the resistance. So, I = V/R = 220/75 = 2.93 amps.

18. The voltage drop across R1 is IR1 = 100.18 = 1.8 volts. The voltage drop across R2 is IR2 = 101.15 = 11.5 volts. The voltage drop across R3 is IR3 = 102 = 20 volts. Therefore, the total voltage in the circuit is V = V1+V2+V3 = 1.8+11.5+20 = 33.3 volts. If R1 gets open, the current flow in the circuit will stop as there will be no current path for the current to flow.

19. To find the voltage drop across R1, we can use Ohm's law, which states that voltage equals current multiplied by resistance. So, V1 = IR1 = 1107000 = 770000 volts. To find the voltage drop across R2, we can use