The time -averaged energy in a sinusoidal electromagnetic wave is

Options

A. Overwhelmingly electrical
B. Slightly more electrical than magnetic
C. Equally divided between the electric and magnetic fields
D. Overwhelmingly magnetic

Answer

To determine the time-averaged energy in a sinusoidal electromagnetic wave, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Concept of Time-Averaged Energy**:
- The time-averaged energy in an electromagnetic wave is often associated with its intensity. Intensity (I) is defined as power per unit area.

2. **Defining Intensity**:
- The intensity (I) of an electromagnetic wave can be expressed mathematically as:
\[ I = \frac{P}{A} \]
where \( P \) is the power of the wave and \( A \) is the area over which the power is distributed.

3. **Components of the Electromagnetic Wave**:
- An electromagnetic wave consists of an electric field (E) and a magnetic field (B). These fields oscillate sinusoidally and are perpendicular to each other and to the direction of wave propagation.

4. **Energy Distribution**:
- The total energy in an electromagnetic wave is equally distributed between the electric field and the magnetic field. This means that the average energy density associated with the electric field is equal to that associated with the magnetic field.

5. **Conclusion**:
- Therefore, the time-averaged energy in a sinusoidal electromagnetic wave is equally divided between the electric field and the magnetic field. This leads us to conclude that the correct answer is that the time-averaged energy is equally divided between the electric and magnetic fields.

### Final Answer:
The time-averaged energy in a sinusoidal electromagnetic wave is equally divided between the electric field and the magnetic field.

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