Question

A material used for making heating elements of electrical heating devices should have :

• A. High resistivity and high melting point.
• B. High resistivity and low melting point.
• C. Low resistivity and high melting point.
• D. Low resistivity and low melting point.

Hint:

A heating element must resist current well and withstand high temperatures without melting.

Answer 1

The Correct Option is A

A good heating element (like nichrome) used in electrical appliances must have: - High resistivity, so that it can produce more heat when current passes through it (according to Joule’s law of heating: $H = I^2Rt$). - High melting point, so that it does not melt or get damaged at high temperatures when it gets heated up. Materials like nichrome have high resistivity and a high melting point, which makes them suitable for use in heating elements such as electric irons, heaters, and toasters. Therefore, the correct answer is High resistivity and high melting point.