State any one property which is common to all electromagnetic waves.

Explanation

**Step-by-Step Solution:**

1. **Understanding Electromagnetic Waves**: Electromagnetic waves are waves that consist of oscillating electric and magnetic fields and can travel through a vacuum or a medium.

2. **Identifying Common Properties**: To answer the question, we need to identify a property that is shared by all types of electromagnetic waves, such as radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

3. **Speed of Electromagnetic Waves**: One of the fundamental properties of electromagnetic waves is that they all travel at the same speed in a vacuum. This speed is known as the speed of light, denoted by 'c'.

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