On the section of the electrical circuit, a light bulb and a resistor are connected in series.

On the section of the electrical circuit, a light bulb and a resistor are connected in series. The resistance of the light bulb (R = 12 ohms), and the resistance of the resistor (R = 72 ohms). Determine the voltage across the resistor (U -?), If the voltage across the light bulb is U = 2.5V

Initial data: Rl (light bulb resistance) = 12 Ohm; Rp (resistor resistance) = 72 Ohm; Ul (voltage on the light bulb) = 2.5 V; a light bulb and a resistor are connected in series.

1) Determine the current strength in the section of the electric circuit: I = Il = Iр = Ul / Rl = 2.5 / 12 = 0.2083 A.

2) Determine the voltage across the resistor: Uр = I * Rр = 0.2083 * 72 = 15 V.

Answer: The voltage across the resistor is 15 V.