Which of the following relations is correct?

Options

A. E=mc
B. `E = mc^(2)`
C. `E = 2mc^(2)`
D. `E = mc^(2)//4`

Explanation

To solve the question "Which of the following relations is correct?" we need to analyze each of the given options regarding the relationship between energy and mass as per Einstein's theory of relativity.

### Step-by-Step Solution:

1. **Understand the context**: The question asks for the correct relation between energy and mass. This is a fundamental concept in physics, particularly in the theory of relativity.

2. **Recall Einstein's equation**: According to Einstein's theory of relativity, the relationship between energy (E) and mass (m) is given by the equation:
\[ E = mc^2 \]
where \( c \) is the speed of light in a vacuum.

3. **Evaluate the options**:
- **Option A**: \( E = mc \) - This is incorrect as it does not account for the speed of light squared.
- **Option B**: \( E = mc^2 \) - This is the correct relation as per Einstein's theory.
- **Option C**: \( E = 2mc^2 \) - This is incorrect; it suggests that energy is double the mass-energy equivalence.
- **Option D**: \( E = \frac{mc^2}{4} \) - This is also incorrect; it suggests that energy is a quarter of the mass-energy equivalence.

4. **Conclusion**: After evaluating all the options, the correct relation is:
\[ E = mc^2 \]
Therefore, the answer is **Option B**.

### Final Answer:
The correct relation is \( E = mc^2 \) (Option B).