The mass of an atomic nucleus is less than the sum of the masses of its constituents. Thus mass defect is converted in to

Options

A. heat energy
B. light energy
C. electrical energy
D. energy which binds nucleons together

Answer

To solve the question regarding the mass defect of an atomic nucleus and what it converts into, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Mass Defect**:
- The mass of an atomic nucleus is less than the sum of the masses of its individual constituents (protons and neutrons). This difference in mass is known as the mass defect (Δm).

2. **Defining Mass Defect**:
- Mathematically, if we denote the mass of the nucleus as \( M \), the mass of \( z \) protons as \( z \cdot m_p \), and the mass of \( n \) neutrons as \( n \cdot m_n \), we can express the mass defect as:
\[ \Delta m = (z \cdot m_p + n \cdot m_n) - M \]

3. **Conversion of Mass Defect**:
- According to Einstein's mass-energy equivalence principle, mass can be converted into energy. The mass defect (Δm) is converted into energy, specifically binding energy, which is the energy required to hold the nucleus together.

4. **Binding Energy**:
- The binding energy (E) associated with the mass defect can be calculated using Einstein's equation:
\[ E = \Delta m \cdot c^2 \]
where \( c \) is the speed of light in a vacuum.

5. **Stability of the Nucleus**:
- The binding energy is crucial for the stability of the nucleus. It counteracts the electrostatic repulsion between the positively charged protons, thus keeping the nucleus intact.

6. **Conclusion**:
- Therefore, the mass defect is converted into binding energy, which is the energy that binds the nucleus together and contributes to its stability.

### Final Answer:
The mass defect is converted into binding energy, which binds the nucleus together.