Question

Which of the following electromagnetic waves has the longest wavelength?
1. Gamma rays
2. Light rays
3. Ultra - violet
4. Infrared

Answer 1

Correct Answer - Option 4 : Infrared

The correct answer is Infrared.

• Radio waves, infrared rays, visible light, ultraviolet rays, X-rays, and gamma rays are all types of electromagnetic radiation.
  • Radio waves have the longest wavelength, and gamma rays have the shortest wavelength.
    
• Red has the longest wavelength and violet has the shortest wavelength.
  • When all the waves are seen together, they make white light. Ultraviolet (UV) light—is radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400.
• The frequency of a wave is related to its wavelength.
  • The more crests that pass a point per second, the closer together they must be. Thus the higher the frequency the shorter the wavelength. Waves with lower frequencies have longer wavelengths.
• Audio frequencies are expressed in hertz (Hz); although experts don't always agree on specific values, the overall consensus is that high-frequency sounds start at 2,048 Hz. Moving backwards, the range between the lowest treble and 256 Hz is known as midrange audio.
• The human ear perceives frequencies between 20 Hz (lowest pitch) to 20 kHz (highest pitch).
  • All sounds below 20 Hz are qualified as infrasounds, although some animals (ex. mole-rat, or elephant) are hearing them.