Arrange the following materials in increasing order of their resistivities.
(A) Tungsten
(B) Aluminium
(C) Gold
(D) Copper
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (D)\( \lt \)(C)\( \lt \)(B)\( \lt \)(A)
All four are metals (conductors), so the comparison rests on their resistivities at room temperature (in \( \Omega\,\mathrm{m} \)):
\( (D)\ \text{Copper}: 1.7\times10^{-8} \)
\( (C)\ \text{Gold}: 2.4\times10^{-8} \)
\( (B)\ \text{Aluminium}: 2.7\times10^{-8} \)
\( (A)\ \text{Tungsten}: 5.6\times10^{-8} \)
Copper is among the best conductors (only silver is better), while tungsten has the highest resistivity of the four, which is why it is used for filaments.
The increasing order is D, C, B, A.