Question

"Electrical resistivity is a charateristics property of material". Explain this statement
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Answer 1

Answer:

Electrical resistivity: It is a property of material. It is the strength of material to oppose the flowing current in the conductor made by the material. It does not depends on shape and size of conductor. It depends on nature and temperature of the conductor.

Answer 2

Answer:

Metals and alloys have very low resistivity in the range of 10‒ 8 Ω m to 10‒ 6 Ω m.

→ A good conductor of electricity has low resistivity and a poor conductor of electricity has a high resistivity.

→ Insulators like rubber and glass have resistivity of the order of 1012 Ω m to 1017 Ω m.

→ Copper and aluminium have very low resistivity (of the order of 10‒ 8 Ω m) due to which they are very good conductors of electricity.

[And hence they are generally used for electrical transmission lines.]

→ Resistivity of alloys (e.g., Nichrome, constantan) is higher (of the order of 10‒ 6 Ω m) than those of pure metals from which they are made.

[For this reason, they are commonly used in electrical heating devices like electric iron, toasters, etc.]

→ The resistivity of semiconductors like silicon (Si) and germanium (Ge) is between those of conductors and insulators and decreases on increasing the temperature.

[And hence they are used for making (PN junction) diodes and transistors.]