Which of the following substances has highest value of Young's modulus?

Options

A. Aluminium
B. Iron
C. Copper
D. Steel

Explanation

To determine which substance has the highest value of Young's modulus, we can follow these steps:

### Step 1: Understand Young's Modulus
Young's modulus (E) is a measure of the stiffness of a solid material. It is defined as the ratio of tensile stress (force per unit area) to tensile strain (proportional deformation in length). Higher values of Young's modulus indicate stiffer materials.

### Step 2: Gather Data
We need to compare the Young's modulus values for the substances in question. The values for the materials provided are:
- Aluminum: 70 GPa
- Copper: 120 GPa
- Iron: 190 GPa
- Steel: 200 GPa

### Step 3: Compare the Values
Now, we will compare the Young's modulus values:
- Aluminum: 70 GPa
- Copper: 120 GPa
- Iron: 190 GPa
- Steel: 200 GPa

### Step 4: Identify the Highest Value
From the comparison, we see that:
- Steel has the highest Young's modulus value at 200 GPa.

### Step 5: Conclusion
Thus, the substance with the highest value of Young's modulus among the options given is **Steel**.

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