If the angle of prism is `60^(@)` and the angle of minimum deviation is `40^(@)` , the angle of refraction will be

Options

A. `30^(@)`
B. `60^(@)`
C. `100^(@)`
D. `120^(@)`

Answer

To solve the problem, we need to find the angle of refraction (r) when the angle of the prism (A) is given as 60 degrees, and the angle of minimum deviation (D) is given as 40 degrees.

### Step-by-Step Solution:

1. **Understanding the Relationship**:
The angle of refraction (r) at the prism’s surface can be determined using the formula:
\[ r = \frac{A}{2} \]
where A is the angle of the prism.

2. **Substituting the Given Values**:
We know that the angle of the prism (A) is 60 degrees. Therefore, we can substitute this value into the formula:
\[ r = \frac{60^\circ}{2} \]

3. **Calculating the Angle of Refraction**:
Now, we perform the calculation:
\[ r = 30^\circ \]

4. **Conclusion**:
Thus, the angle of refraction (r) is 30 degrees.

### Final Answer:
The angle of refraction is \( 30^\circ \).

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