Electromagnetic Waves and Wavelength

Electromagnetic waves are disturbances that transfer energy through space and matter. They are created by the vibration of electric and magnetic fields. These waves travel at the speed of light in a vacuum.

The electromagnetic spectrum is a classification of electromagnetic waves based on their frequency and wavelength. There is an inverse relationship between frequency and wavelength: as frequency increases, wavelength decreases, and vice versa. Energy carried by electromagnetic waves is directly proportional to frequency, so higher frequency means higher energy, and thus shorter wavelength means higher energy.

Electromagnetic Spectrum Order by Wavelength

Let's list the common types of electromagnetic waves in order from the longest wavelength to the shortest wavelength:

• Radio waves (longest wavelength, lowest frequency/energy)
• Microwaves
• Infrared radiation
• Visible light
• Ultraviolet radiation
• X-rays
• Gamma rays (shortest wavelength, highest frequency/energy)

The question asks which of the given options has the longest wavelength. Let's examine the options provided in relation to the electromagnetic spectrum order:

• Gamma rays: These are at the high-frequency, short-wavelength end of the spectrum.
• Light rays (Visible light): This is in the middle of the spectrum, between infrared and ultraviolet.
• Ultra-violet: These are higher frequency and shorter wavelength than visible light.
• Infrared: These are lower frequency and longer wavelength than visible light.

Comparing the positions of these waves in the spectrum from longest wavelength to shortest: Infrared > Visible Light > Ultra-violet > Gamma rays.

Therefore, among the given options, Infrared radiation has the longest wavelength.