Q101
General SciencePhysics
All electromagnetic waves have the same
- a.frequency
- b.amplitude
- c.wavelength in vacuum
- d.speed in vacuum
Answer: (D) speed in vacuum
All electromagnetic waves (radio, microwave, infrared, visible light, ultraviolet, X-rays, gamma rays) travel in vacuum with the same speed, $c \approx 3\times10^8$ m/s. They differ in frequency and wavelength, which are related by $c = \nu\lambda$, so a higher frequency means a shorter wavelength; amplitude depends on the intensity of the source. They are transverse waves and need no material medium.