Question

Arrange the following materials in the increasing order of their resistivity: (A) Copper, (B) Platinum, (C) Silver, (D) Aluminium.

• A. (A), (C), (B), (D)
• B. (C), (A), (D), (B)
• C. (C), (B), (A), (D)
• D. (B), (D), (A), (C)

Answer 1

The Correct Option is B

The resistivity of a material is a measure of how strongly it opposes the flow of electric current. To solve this problem, we need to compare the resistivities of the given materials: (A) Copper, (B) Platinum, (C) Silver, and (D) Aluminium. The correct answer choice (C), (A), (D), (B) indicates the increasing order of their resistivity as Silver, Copper, Aluminium, and Platinum. Here's the explanation for the arrangement: 

• Silver (C) has the lowest resistivity among the listed materials, making it the best conductor.
• Copper (A) follows Silver in terms of low resistivity and is also an excellent conductor, used widely in electrical wiring.
• Aluminium (D) has higher resistivity than both Silver and Copper but is still used in power lines due to its lower density and cost.
• Platinum (B) has the highest resistivity among these materials. While it's not commonly used for conventional wiring due to its high resistivity and cost, its stability and corrosion resistance make it valuable for specific applications.

The arrangement (C), (A), (D), (B) is thus based on increasing resistivity.

Answer 2

The resistivity (\( \rho \)) of a material is a measure of how strongly it opposes the flow of electric current. Here are the typical resistivity values for the given materials at room temperature (20°C):

Material	Resistivity (\( \rho \))	Unit
Silver (C)	\( 1.59 \times 10^{-8} \)	Ω·m
Copper (A)	\( 1.68 \times 10^{-8} \)	Ω·m
Aluminium (D)	\( 2.65 \times 10^{-8} \)	Ω·m
Platinum (B)	\( 1.06 \times 10^{-7} \)	Ω·m

Step 1: Compare the resistivity values

From the table, we can see the order from lowest to highest resistivity is:

Silver (C) < Copper (A) < Aluminium (D) < Platinum (B)

Step 2: Final Order

Increasing order of resistivity: C (Silver) < A (Copper) < D (Aluminium) < B (Platinum)