To find the total voltage of the circuit, we can use Ohm's Law:

$V = I \cdot R_{\text{total}}$

Where:

• $V$ is the voltage across the entire circuit,
• $I$ is the total current,
• $R_{\text{total}}$ is the total resistance in the circuit.

Since the resistors are connected in series, the total resistance is the sum of the individual resistances:

$R_{\text{total}} = R_1 + R_2 + R_3$

Substitute the given values:

$R_{\text{total}} = 300 \, \Omega + 90 \, \Omega + 150 \, \Omega = 540 \, \Omega$

Now, using the total current of 1.2 amps:

$V = 1.2 \, \text{A} \times 540 \, \Omega = 648 \, \text{V}$

Thus, the total voltage across the circuit is 648 volts.

Would you like more details on how this was calculated or have any follow-up questions?

Here are five related questions:

1. How does the total resistance in a series circuit change if more resistors are added?
2. What would happen to the total current if the voltage remained the same but the total resistance increased?
3. How do you calculate voltage drops across individual resistors in a series circuit?
4. How does Ohm's Law apply in parallel circuits compared to series circuits?
5. How would the total current change if the resistances of the resistors were reduced by half?

Tip: In a series circuit, the current is the same through all resistors, but the voltage divides according to the resistance values.