Question

which of these is evidence that electromagnetic waves do not require a medium? light cannot be seen through a solid wall. sound can be heard through a solid wall. radiation from the sun reaches the earth.

Explanation:

1. Recall the difference between electromagnetic waves (like light, solar radiation) and mechanical waves (like sound). Electromagnetic waves don't need a medium, mechanical waves do.
2. Analyze Option A: Light not passing through a wall relates to opacity, not medium requirement.
3. Analyze Option B: Sound (mechanical wave) needs a medium; hearing through a wall shows sound travels through solids (a medium), so this supports sound needing a medium, not EM waves.
4. Analyze Option C: Space between Sun and Earth is a near - vacuum (no medium). Solar radiation (electromagnetic) reaching Earth shows EM waves can travel without a medium.

Answer:

C. Radiation from the Sun reaches the Earth.