An electromagnetic wave can be produced, when charge is

Options

A. moving with a constant velocity
B. moving in a circular orbit
C. falling in an electric field
D. both (b) and (c)

Explanation

To solve the question "An electromagnetic wave can be produced when charge is:", we need to analyze the options provided and understand the conditions under which electromagnetic waves are generated.

### Step-by-Step Solution:

1. **Understanding Electromagnetic Waves**:
Electromagnetic waves are produced by the acceleration of electric charges. When a charge accelerates, it creates a changing electric field, which in turn produces a changing magnetic field, leading to the formation of electromagnetic waves.

2. **Analyzing the Options**:
- **Option A: Moving with a constant velocity**:
When a charge moves with a constant velocity, it is not accelerating. Since there is no change in velocity, it does not produce electromagnetic waves.
- **Option B: Moving in a circular orbit**:
A charge moving in a circular orbit is constantly changing its direction of motion. This change in direction constitutes acceleration (centripetal acceleration), which means it will produce electromagnetic waves.
- **Option C: Falling in an electric field**:
A charge falling in an electric field experiences a force (due to the electric field) that causes it to accelerate. This acceleration also results in the production of electromagnetic waves.
- **Option D: Both B and C**:
Since both options B and C involve acceleration, they will both produce electromagnetic waves.

3. **Conclusion**:
Based on the analysis:
- Option A does not produce electromagnetic waves.
- Options B and C do produce electromagnetic waves.
- Therefore, the correct answer is **Option D: Both B and C**.

### Final Answer:
An electromagnetic wave can be produced when charge is **both moving in a circular orbit (Option B) and falling in an electric field (Option C)**. Thus, the correct answer is **Option D: Both B and C**.

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