Question

Among the following, the waves responsible for energy transfer in vacuum are

• A. infrared waves.
• B. sound waves.
• C. SONAR waves.
• D. seismic waves.

Hint:

Remember that all forms of light (radio, microwave, infrared, visible, ultraviolet, X-rays, gamma rays) are electromagnetic waves and can travel through the vacuum of space.

Answer 1

The Correct Option is A

Step 1: Read the key word, vacuum.
The question wants waves that can carry energy across empty space, where there are no atoms or molecules at all.

Step 2: Split waves into two families.
Waves are either mechanical, needing a material to wobble, or electromagnetic, which are self-sustaining oscillations of electric and magnetic fields.

Step 3: Check sound waves.
Sound is a pressure wave in air or other matter. With no medium, there is nothing to compress, so sound cannot cross a vacuum.

Step 4: Check SONAR and seismic waves.
SONAR is sound in water and seismic waves travel through rock and the Earth's body. Both are mechanical and both need a medium, so they are ruled out.

Step 5: Check infrared waves.
Infrared is a part of the electromagnetic spectrum, just like visible light. It needs no medium and travels freely through vacuum, which is exactly how the Sun's heat reaches us.

Step 6: Pick the answer.
Only the infrared waves qualify. \[ \boxed{\text{Infrared waves}} \]