Heat in a conductor is produced on the passage of electric current due to

reactance
capacitance
impedance
resistance

The correct answer is: D. resistance.

Resistance is the opposition to the flow of electric current in a conductor. It is measured in ohms (Ω). The higher the resistance, the lower the current flow.

When an electric current flows through a conductor, it causes the atoms in the conductor to vibrate. This vibration produces heat. The amount of heat produced is proportional to the square of the current and the resistance of the conductor.

Reactance is the opposition to the flow of alternating current (AC) in a conductor. It is caused by the inductance and capacitance of the conductor. Inductance is the opposition to a change in current, while capacitance is the opposition to a change in voltage.

Impedance is the total opposition to the flow of AC in a conductor. It is the vector sum of the resistance and reactance.

In conclusion, heat in a conductor is produced on the passage of electric current due to resistance.