Question

some electric stoves have a flat ceramic surface with heating elements hidden beneath. A pot placed over a heating element will be heated, while it is safe to touch the surface only a few centimeters away. Why is ceramic, with a conductivity less that of a metal but greater than of a good insulator, an ideal choice for the stove top?

Answer 1

Electric stoves are the devices which convert electrical energy into heat. The heat generated by the stoves is used for various works like cooking food, heating water and many more.

The heating element of the electric stoves is hidden beneath the flat surface of ceramic to keep the heating element for uniform heating the pot. Ceramic used in the stove is mostly insulator.

For construction of the ideal stove it is kept conductivity of the ceramic frame with conductivity better than that of the insulator bur less than that of conductor is used to avoid current flow to the flat surface and heat flow to the surface. The heat loss to the beneath of the flat surface is minimized by doing so.

Hence for the maximum utilization of the electricity keeping other parameters constant and make it safe to use, it is better to use the flat surface of the ceramic have conductivity greater than that of insulator and less than that of conductor.

Answer 2

We know that in these electric stoves, the electrical energy is converted to heat. We know that ceramic has a greater conductivity means it can conduct the heat. In simple words, the conduction of heat can take place easily. When electricity is converted to heat inside the stove, that heat will travel to the ceramic top and will conduct throughout the plate thus making it hot.

Further, It spread the heat over the area above the heating elements, maintaining the temperature there, but does not spread the heat much beyond the heating elements.