The electrical resistivity of few material is given below in ohm-metre. Which of these materials can be used for making elements of a heating device. A 6.84 × 10-8 Ωm B 1.60 × 10-8 Ωm C 1.00 × 10-4 Ωm D 2.50 × 1012 Ωm E 4.40 × 10-5 Ωm F 2.30 × 1017 Ωm
A material having highest value of resistivity is used for making element of heating devices; therefore, material C will be used. D and F are insulators since they have very high values of resistivity.
