Radiation Wavelength Comparison Explained

This question asks us to identify which type of electromagnetic radiation has the longest wavelength among the given options: X-rays, Ultraviolet, Micro Wave, and Infra-red.

Understanding the Electromagnetic Spectrum

The electromagnetic (EM) spectrum arranges different types of EM radiation based on their wavelength (\(\lambda\)) and frequency (\(f\)). These two properties are inversely proportional; as wavelength increases, frequency decreases, and vice versa. Energy (\(E\)) carried by the radiation is directly proportional to its frequency (E = hf, where \(h\) is Planck's constant).

The general order of the EM spectrum from shortest wavelength (highest frequency, highest energy) to longest wavelength (lowest frequency, lowest energy) is:

• Gamma Rays
• X-rays
• Ultraviolet (UV)
• Visible Light
• Infra-red (IR)
• Microwaves
• Radio Waves

Comparing the Given Radiation Types

Let's compare the wavelengths of the specific radiations mentioned in the options:

• X-rays: Have relatively short wavelengths, typically ranging from about \(10^{-8}\) meters to \(10^{-11}\) meters.
• Ultraviolet (UV) radiation: Has wavelengths longer than X-rays but shorter than visible light. The wavelength range is approximately \(10^{-7}\) meters to \(4 \times 10^{-7}\) meters.
• Infra-red (IR) radiation: Has wavelengths longer than visible light and UV radiation. Its range is roughly \(7 \times 10^{-7}\) meters to \(1 \times 10^{-3}\) meters.
• Micro Waves: Have longer wavelengths than Infra-red radiation. Their wavelength range is typically from about 1 millimeter (\(10^{-3}\) meters) to 1 meter.

Wavelength Ranking

Based on their positions in the electromagnetic spectrum, we can rank the given options by their wavelength, from shortest to longest:

Conclusion

Comparing the four types of radiation, Micro Waves possess the longest wavelengths. X-rays have the shortest wavelengths among the choices, followed by Ultraviolet, then Infra-red, and finally Microwaves have the longest.