All of the following apply to a current of electricity EXCEPT

• A. Heat is produced in all parts of the circuit
• B. Chemical action is produced by a direct current
• C. A magnetic needle is deflected when brought near a circuit when the current is flowing
• D. Very rapid alternating currents produce no chemical effects

Answer: (D)

Heat being produced in a circuit comes from the resistance that converts part of the electrical energy into heat as current flows through any resistive path. In a circuit, wherever there is resistance, you’ll see heating.

Direct current drives chemical action at the electrodes because the constant direction of flow pushes ions in a steady way, enabling electrochemical reactions such as electrolysis at the electrode surfaces.

A current-carrying wire has a magnetic field around it, so a magnetic needle placed nearby will deflect when the current is flowing. That magnetic effect is a direct consequence of the magnetic field produced by moving charges.

The statement about very rapid alternating currents producing no chemical effects isn’t universally true. Even with rapidly reversing current, chemical activity can occur at electrode interfaces or in the surrounding electrolyte during each half-cycle, and under certain conditions these effects can be observed. Therefore this claim does not consistently apply, making it the exception.