Which of the following electromagnetic waves has the shortest wavelength?

Analysis

The question asks you to identify which of the listed electromagnetic waves has the shortest wavelength. To solve this, we must recall the electromagnetic spectrum and the relationship between wavelength, frequency, and energy.

Concept: The Electromagnetic Spectrum

Electromagnetic waves are arranged in a spectrum based on their frequency and wavelength. The relationship is governed by the wave equation:

Where:

• $c$ is the speed of light (constant).
• $f$ is the frequency.
• $\lambda$ (lambda) is the wavelength.

Because the speed of light is constant, frequency and wavelength are inversely proportional. This means:

• Waves with high frequency have short wavelengths.
• Waves with low frequency have long wavelengths.

The order of the electromagnetic spectrum (from longest wavelength/lowest frequency to shortest wavelength/highest frequency) is:

1. Radio waves
2. Microwaves
3. Infrared rays
4. Visible light
5. Ultraviolet rays
6. X-rays
7. Gamma rays

Step-by-Step Solution

1. Compare the options: • Infrared rays: Located near the low-frequency end of the spectrum (long wavelength). • Visible light: Located in the middle of the spectrum. • Ultraviolet rays: Higher frequency than visible light (shorter wavelength). • Gamma rays: Located at the extreme high-frequency end of the spectrum.
2. Apply the principle: Since Gamma rays have the highest frequency among all electromagnetic waves, they must mathematically possess the shortest wavelength.
3. Conclusion: Comparing the options provided, Gamma rays are the most energetic and have the smallest wavelength.

Exam Tip

Remember the mnemonic "Raging Martians Invaded Venus Using X-ray Guns" to recall the order of the spectrum:

• Radio
• Microwaves
• Infrared
• Visible
• Ultraviolet
• X-rays
• Gamma rays

As you move from left to right in this mnemonic, the frequency increases and the wavelength decreases!