Question

which of the following waves travel at the speed of light?
○ longitudinal waves
○ electromagnetic waves
○ surface waves
○ transverse waves

Explanation:

Electromagnetic waves (e.g., light, radio waves) propagate through a vacuum at the speed of light ($c \approx 3 \times 10^8$ m/s). Longitudinal waves (e.g., sound) require a medium and travel slower; surface waves (e.g., water waves) are mechanical and medium-dependent; transverse waves include non-electromagnetic types (e.g., string waves) that do not reach light speed.

Answer:

B. electromagnetic waves