Which heating method is employed for non-conducting materials?
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Answer: D. Dielectric heating
Explanation
Dielectric heating uses high-frequency electric fields to heat non-conducting insulating materials. Alternating electric fields cause rapid molecular dipole rotation and friction within the insulator. This internal molecular friction generates thermal energy uniformly throughout the non-conducting material. Dielectrics are electrical insulators that become polarized when exposed to external electric fields. High-frequency radio wave generators supply the alternating electric fields required for this process. Volumetric heating allows thick non-conducting materials to be heated evenly without surface scorching.
Dielectric heating is used extensively in plywood manufacturing, food processing, and plastic welding. Industrial radio-frequency dryers cure adhesives in wood products rapidly and uniformly. This method bypasses the poor thermal conductivity of insulators by generating heat internally. Option A is incorrect because eddy current heating requires conductive materials rather than insulators. Option B is incorrect because arc heating generates excessive temperatures that would destroy insulators. Option C is incorrect because induction heating is restricted strictly to electrically conductive materials.
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- Engineering
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- Electrical Engineering
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