Capacitive method is thermal through which mechanism?

Capacitive method is thermal through which mechanism?

• A. Convection
• B. Conduction
• C. Radiation
• D. Evaporation

Answer: (A)

Capacitive diathermy heats tissue by applying an alternating electric field across tissue placed between two plates. The electric field causes currents and molecular dipoles in the tissue to move, converting electrical energy into heat right in the tissue (dielectric/resistive heating). That heat then spreads to surrounding tissues mainly by conduction, as heat moves through the tissue from the heated area to adjacent areas. So the primary heat-transfer mechanism is conduction. Convection would require moving fluid, radiation would be heat transfer by emitted energy from a surface, and evaporation involves vaporizing surface moisture—none of which are the main process in capacitive heating.

Capacitive diathermy heats tissue by applying an alternating electric field across tissue placed between two plates. The electric field causes currents and molecular dipoles in the tissue to move, converting electrical energy into heat right in the tissue (dielectric/resistive heating). That heat then spreads to surrounding tissues mainly by conduction, as heat moves through the tissue from the heated area to adjacent areas. So the primary heat-transfer mechanism is conduction. Convection would require moving fluid, radiation would be heat transfer by emitted energy from a surface, and evaporation involves vaporizing surface moisture—none of which are the main process in capacitive heating.