Question

which is one characteristic shared by electromagnetic and mechanical waves?
○ both have a frequency and amplitude.
○ both move due to particles bumping into each other.
○ both are formed by charged particles.
○ both occur as a result of a disturbance.

Explanation:

1. Analyze Option 1: Electromagnetic waves (like light) and mechanical waves (like sound) both have frequency (number of oscillations per unit time) and amplitude (maximum displacement from equilibrium), so this is a valid shared characteristic.
2. Analyze Option 2: Mechanical waves require particle interaction (e.g., sound in air, particles bump), but electromagnetic waves (e.g., light) don't need a medium or particle bumping—they can travel through vacuum via oscillating electric and magnetic fields. So this is incorrect.
3. Analyze Option 3: Electromagnetic waves are related to charged particles (oscillating charges produce EM waves), but mechanical waves (e.g., water waves, sound in air) aren't formed by charged particles. So this is incorrect.
4. Analyze Option 4: A "disturbance" is vague. Mechanical waves form from a disturbance (e.g., plucking a string), but electromagnetic waves form from accelerating charges, not a "disturbance" in the same sense. Frequency and amplitude are more fundamental shared wave characteristics. So Option 1 is better.

Answer:

A. Both have a frequency and amplitude.