On a weight - to - weight basis, the electrical conductitity of aluminium is

Options

A. half that of copper
B. equal to that of copper
C. twice that of copper
D. ten times that of copper

Answer

To determine the electrical conductivity of aluminum on a weight-to-weight basis in comparison to copper, we can follow these steps:

### Step 1: Understand Electrical Conductivity
Electrical conductivity is a measure of a material's ability to conduct electric current. Metals, including aluminum and copper, are good conductors due to the presence of free electrons that can move easily through the material.

**Hint:** Remember that conductivity is influenced by the number of free electrons in the material.

### Step 2: Compare Aluminum and Copper
Both aluminum and copper are metals, but they have different properties. While copper is often considered the standard for electrical conductivity, aluminum is also a good conductor, though it is generally less conductive than copper.

**Hint:** Consider the relative conductivity of aluminum and copper based on their atomic structure and electron configuration.

### Step 3: Reference Values
The electrical conductivity of copper is approximately 5.8 × 10^7 S/m, while the conductivity of aluminum is about 3.5 × 10^7 S/m. However, when comparing on a weight-to-weight basis, we need to consider the density of both metals.

**Hint:** Look up the densities of aluminum and copper to understand how their mass affects conductivity.

### Step 4: Weight-to-Weight Basis Calculation
When comparing on a weight-to-weight basis, we need to account for the fact that aluminum is less dense than copper. The conductivity of aluminum is approximately 60% that of copper when considering their volume. However, when comparing equal weights, aluminum has a higher conductivity due to its lower density.

**Hint:** Remember that the lower density of aluminum means that for the same weight, there are more aluminum atoms available to conduct electricity.

### Step 5: Conclusion
On a weight-to-weight basis, the electrical conductivity of aluminum is approximately twice that of copper. This is because, although copper has a higher conductivity per unit volume, aluminum's lower density allows for a greater number of conducting electrons per unit weight.

**Final Answer:** The electrical conductivity of aluminum on a weight-to-weight basis is **twice that of copper**.