Question

Which of the following is the best conductor of electricity?
A. Au
B. Al
C. Ag
D. Ar

Answer 1

Hint: Compare the values of resistivity a metal offers in order to compare and find the best conductor amongst the options.

Complete step by step answer:
The ease of movement of electrons in metals defines the conductivity of it. When a potential difference is applied to a metal at certain points, the electrons will move and allow electricity to flow. Materials with high electron mobility are good conductors and materials with low or negligible electron mobility are referred to as insulators.
Copper, Silver, Aluminium, Gold, Steel and Brass are common conductors of electricity. Individual properties make each ideal for specific purposes. Copper and Silver are most commonly used conductors.
A physical quantity which makes it easier to select the best conductor is the resistivity of a metal. Resistivity is defined as a measure of the resisting power of a specified material to the flow of an electric current. Good conductors do not resist the flow of current. Therefore, the lesser the resistivity of a metal, the better conductor it is.
The following values of resistivity will help in determining the correct answer:
Material Resistivity
Silver (Ag) \[1.59\times {{10}^{-8}}\Omega m\]
Copper (Cu) \[1.68\times {{10}^{-8}}\Omega m\]
Gold (Au) \[2.2\times {{10}^{-8}}\Omega m\]
Aluminium (Al) \[2.65\times {{10}^{-8}}\Omega m\]
Therefore, the correct option for this question is option C.
Note: Do not confuse copper to be the best conductor because you have observed copper being used in electrical wiring. Silver is the best conductor, but since it is expensive, copper is used.