Question 1 (3 points)

In the circuit shown above, a battery with a voltage ΔVbat = 12 V is connected to the circuit with resistance R1 = 21 ohms, unknown resistors R2 and R3, and an open switch connected to R3.

The volt meter measuring the potential difference between the points A and B gives ΔVAB = 0.60 ΔVbat.

What is the current flowing through the battery?

Give your answer in Amps to three signficant digits. Do not include units in your answer.

                           

Question 2 (3 points)

 

In the circuit shown above, a battery with a voltage ΔVbat = 12 V is connected to the circuit with resistance R1 = 13 ohms, unknown resistors R2 and R3, and an open switch connected to R3.

The volt meter measuring the potential difference between the points A and B gives ΔVAB = 0.85 ΔVbat.

What is the value of the resistance of R2?

Give your answer in Ohms to three signficant digits. Do not include units in your answer.

                             

Question 3 (3 points)

 

In the circuits shown above, a battery with a voltage ΔVbat is connected to the circuit with resistances R1, R2, and R3, and a switch connected to R3. In the circuit on the left, the switch is open and in the circuit on the right the switch is closed.

For which circuit, if either, will the voltage read by the volt meter be largest?

Question 3 options: - Switch Closed (Right), because the total resistance is larger for this circuit

- The voltages are the same because when the switch is closed the resistance increases and the current decreases

- Switch Open (Left), because the total current is larger for this circuit - Switch Closed (Right), because the battery voltage is larger for this circuit - Switch Open (Left), because the total resistance is larger for this circuit

- Switch Closed (Right), because the current is the same in both circuits and the resistance connected to the voltmeter is larger for this circuit

- The voltages are the same because R2 and R3 are in parallel

- The voltages are the same because when the switch is closed the resistance decreaseas and the current increases

- Switch Open (Left), because the current is the same in both circuits and the resistance connected to the voltmeter is larger for this circuit

- Switch Open (Left), because the battery voltage is larger for this circuit - Switch Closed (Right), because the total current is larger for this circuit                      

Question 4 (3 points)

 

In the circuits shown above, a battery with a voltage ΔVbat = 12 V is connected to the circuit with resistances R1 = R2 = 40 ohms, unknown resistor R3, and a switch connected to R3.

The volt meter measures the potential difference between the points A and B, ΔVAB.

Define ΔVO be the reading on the voltmeter when the switch is open and ΔVC be the reading on the voltmeter when the switch is closed.

If the ratio (ΔVC / ΔVO) = 0.45, what is the value of the resistance of R3?

Give your answer in ohms to three signficant digits. Do not include units in your answer.

                                             

Question 5 (3 points)

 

In the circuit shown above, a battery with a voltage ΔVbat = 12 V is connected to the circuit with resistances R1 = 7 Ohms, R2 = 15 Ohms, and R3 = 40 Ohms.

The volt meter measures the potential difference between the points A and B, ΔVAB.

What is the power lost in the resistor R3?

Give your answer in Watts to three signficant digits. Do not include units in your answer.