Select the correct reason why diamond appears to sparkle in the dark

Options

A. It has a low critical angle of `24^(@)`
B. Due to the light getting entrapped inside the diamond as a result of successive total internal reflection
C. Due to refraction of light
D. both 1 and 2

Explanation

To solve the question "Select the correct reason why diamond appears to sparkle in the dark," we will analyze the properties of diamonds and the behavior of light with respect to them.

### Step-by-Step Solution:

1. **Understanding Diamond's Properties**:
Diamonds are known for their brilliance and sparkle. This is primarily due to their ability to refract and reflect light.

**Hint**: Consider the optical properties of diamonds and how they interact with light.

2. **Critical Angle**:
Diamonds have a low critical angle of approximately 24 degrees. The critical angle is the angle of incidence above which total internal reflection occurs.

**Hint**: Recall the definition of critical angle and how it relates to total internal reflection.

3. **Total Internal Reflection**:
When light enters a diamond at an angle greater than the critical angle, it does not exit the diamond but instead reflects back into it. This process is known as total internal reflection.

**Hint**: Think about what happens to light when it strikes the boundary of two different media at angles greater than the critical angle.

4. **Entrapment of Light**:
As light reflects within the diamond due to total internal reflection, it gets entrapped inside the diamond, enhancing its sparkle.

**Hint**: Consider how the repeated reflections contribute to the overall brightness and sparkle of the diamond.

5. **Analyzing the Options**:
- **Option 1**: "It has a low critical angle which is 24 degrees." - This is correct.
- **Option 2**: "Due to light getting entrapped inside the diamond as a result of successive total internal reflection." - This is also correct.
- **Option 3**: "Due to refraction of light." - This is incorrect because refraction does not lead to light being entrapped.
- **Option 4**: "Both option 1 and 2." - This is the most appropriate answer as it combines the correct reasons.

**Hint**: Evaluate each option based on the principles of optics and the behavior of light in diamonds.

6. **Conclusion**:
The correct answer is **Option 4**: "Both option 1 and 2," as both statements accurately describe why diamonds sparkle in the dark.

### Final Answer:
The diamond appears to sparkle in the dark due to its low critical angle and the light getting entrapped inside it as a result of total internal reflection. Therefore, the correct option is **both option 1 and 2**.