How to lay out the answer. Follow the frame, then write it in your own words.
1 · Open in two lines. Dielectric heating uses high-frequency radio waves or microwaves to heat food from inside by making its water molecules oscillate.
2 · Principle. Polar water molecules flip millions to billions of times a second to follow the alternating field; the friction produces heat throughout the food.
3 · Two types.
Radio frequency: 13.56, 27.12, 40.68 MHz; deeper, for large blocks.
Microwave: 915 MHz (industry), 2450 MHz (home).
4 · Draw the principle. [Sketch: magnetron → waveguide → food in metal cavity; water molecules flipping with the field]
5 · Uses. Thawing, tempering, post-baking drying of biscuits, pasteurising packs, killing insects in grain, cooking.
6 · Advantages and limits.
Fast, efficient, less nutrient loss, clean.
Uneven heating, no browning, no metal, costly.
7 · Nutrition link. Short microwave cooking with little water keeps more vitamin C and B vitamins.
8 · Close in one line. Dielectric heating is a quick, clean way to heat food from within.
Scoring tip: Give both frequency sets and three uses; a small labelled sketch adds marks.
