Infrared Radiation Propagation

Steps:

• Identify infrared as electromagnetic radiation, similar to visible light and radio waves.
• Recall that electromagnetic waves travel through vacuum without medium.
• Note that infrared passes through gases like air, enabling remote controls and heat sensing.
• Confirm infrared is blocked by most solids but not all gases or vacuum.

Why D is correct:

• Electromagnetic waves, including infrared, propagate in vacuum (no medium needed) and gases (low absorption, per wave propagation laws).

Why the others are wrong:

• A and B: Incorrect; infrared travels freely in gases like air, as seen in thermal imaging.
• C: False; infrared transmits through gases, not limited to vacuum.

Final answer: D