In a 24-volt circuit with a switch and a coil, what voltage will appear across the coil when the switch is closed?

In a 24-volt circuit with a switch and a coil, what voltage will appear across the coil when the switch is closed?

• A. 0 volts
• B. 12 volts
• C. 24 volts
• D. 48 volts

Answer: (C)

When the switch closes, the coil is connected directly across the 24-volt source, so the loop sees the full supply voltage across the coil. The inductor resists sudden changes in current, so current begins to rise gradually, but the voltage across the coil initially reflects the source voltage. In this simple setup, with the coil as the only load, the voltage across it remains 24 volts (at the moment of closing), and any later change is governed by the coil’s resistance and the circuit dynamics.

When the switch closes, the coil is connected directly across the 24-volt source, so the loop sees the full supply voltage across the coil. The inductor resists sudden changes in current, so current begins to rise gradually, but the voltage across the coil initially reflects the source voltage. In this simple setup, with the coil as the only load, the voltage across it remains 24 volts (at the moment of closing), and any later change is governed by the coil’s resistance and the circuit dynamics.