What is the circuit current in a DC series circuit where R = 40 ohms and E = 120 V?

To find the circuit current in a DC series circuit, you can apply Ohm's Law, which states that the current (I) is equal to the voltage (E) divided by the resistance (R). In this scenario, you have:

• Voltage (E) = 120 V
• Resistance (R) = 40 ohms

Applying Ohm's Law:

[ I = \frac{E}{R} ]

Substituting the given values:

[ I = \frac{120 V}{40 , \text{ohms}} = 3 , \text{amps} ]

This calculation shows that the circuit current is 3 amps, making it the correct answer. Understanding this principle is crucial because it illustrates the relationship between voltage, resistance, and current in a circuit, especially in series configurations where the same current flows through all components.