Question

section 5 - 3 current in a series circuit

1. what is the current through each resistor in a series circuit if the total voltage is 12 v and the total resistance is 120 ω?
2. the current from the source in figure 5 - 69 is 5 ma. how much current does each milliammeter in the circuit indicate?
3. show how to connect a voltage source and an ammeter to the pc board in figure 5 - 64 to measure the current in r1. which other resistor currents are measured by this setup?

Explanation:

Step1: Recall series - circuit current rule

In a series circuit, the current through all components is the same.

Step2: Solve for question 15

Using Ohm's law $I=\frac{V}{R}$, where $V = 12V$ and $R=120\Omega$. So $I=\frac{12}{120}=0.1A = 100mA$. Since it's a series - circuit, the current through each resistor is $100mA$.

Step3: Solve for question 16

In a series circuit, the current is the same throughout. So if the current from the source is $5mA$, each milliammeter in the circuit indicates $5mA$.

Step4: Solve for question 17

To measure the current in $R_1$, connect the positive terminal of the voltage source to one end of $R_1$, and connect the positive terminal of the ammeter to the other end of $R_1$. Connect the negative terminal of the ammeter to the negative terminal of the voltage source. In a series - circuit, when measuring the current in $R_1$, the currents in all other resistors in the same series path are also measured because the current is the same in a series circuit.

Answer:

1. The current through each resistor is $100mA$.
2. Each milliammeter indicates $5mA$.
3. Connect the positive terminal of the voltage source to one end of $R_1$, connect the positive terminal of the ammeter to the other end of $R_1$, and connect the negative terminal of the ammeter to the negative terminal of the voltage source. The currents in all other resistors in the same series path are also measured.