X-rays and infrared rays are both electromagnetic. Which common property do the waves have? Both waves

Step 1: Analyze the question We are asked for a property that X-rays and infrared rays share because both are electromagnetic waves.

Step 2: Key concept All electromagnetic waves (radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays) have these features in common:

• They are transverse waves (not longitudinal).
• They travel at the same speed in a vacuum, c = 3.0 × 10⁸ m/s.
• They need no material medium.
• They differ from one another in frequency and wavelength.

The relationship is c = fλ. Since c is constant, a higher frequency means a shorter wavelength.

Step 3: Check each option

• A. Are longitudinal: Wrong. EM waves are transverse.
• B. Have the same frequency: Wrong. X-rays have a much higher frequency than infrared rays.
• C. Have the same wavelength: Wrong. X-rays have a very short wavelength (about 10⁻¹⁰ m), while infrared is much longer (about 10⁻⁶ to 10⁻³ m).
• D. Travel at the same speed in a vacuum: Correct. Every EM wave travels at 3.0 × 10⁸ m/s in a vacuum.

Step 4: Answer

Exam tip: Remember that EM waves are "transverse, same speed in a vacuum, different f and λ." If a question asks what all EM waves share, think of speed in a vacuum first. If it asks what differs, think of frequency, wavelength, and energy.