Question

Which of the following choices correctly sequences the designated segments of the electromagnetic wave spectrum in an increasing order of their respective photon energies?

• A. \( \text{Radio waves} < \text{Microwaves} < \text{Infrared} < \text{X-rays} \)
• B. \( \text{X-rays} < \text{Infrared} < \text{Microwaves} < \text{Radio waves} \)
• C. \( \text{Microwaves} < \text{Radio waves} < \text{Infrared} < \text{X-rays} \)
• D. \( \text{Radio waves} < \text{X-rays} < \text{Infrared} < \text{Microwaves} \)

Hint:

To remember this order easily during exams, use a simple mnemonic: Roman Men Invented Very Unusual Xray Guns. This stands for Radio, Microwave, Infrared, Visible, Ultraviolet, X-ray, Gamma.

Answer 1

The Correct Option is A

Concept: Electromagnetic waves are synchronized oscillations of electric and magnetic fields traveling through space at the speed of light (\(c\)). The entire spread of these waves is organized into the Electromagnetic Spectrum based on wavelength and frequency characteristics. According to quantum mechanics, the discrete energy (\(E\)) carried by an individual photon is directly proportional to its operational frequency (\(f\)) and inversely proportional to its spatial wavelength (\(\lambda\)): \[ E = hf = \frac{hc}{\lambda} \] where \(h\) is Planck's constant (\(6.626 \times 10^{-34}\,\text{J}\cdot\text{s}\)) and \(c\) is the speed of light in a vacuum (\(3 \times 10^8\,\text{m/s}\)). This relationship means that waves with longer wavelengths have lower frequencies and carry less photon energy. Conversely, shorter wavelengths correspond to higher frequencies and much higher photon energies.

Step 1: Chart the complete standard order of the electromagnetic spectrum. Let's look at the continuous spectrum bands arranged from the longest wavelength (lowest frequency/lowest energy) down to the shortest wavelength (highest frequency/highest energy):
• Radio Waves: Longest wavelength, lowest photon energy scale.
• Microwaves: Millimeter wavelength scale.
• Infrared radiation: Thermal signatures, sits just below visible light.
• Visible Light: Narrow band visible to human eyes (Red to Violet).
• Ultraviolet Rays: Ionizing risk potential, sits just above visible light.
• X-Rays: High penetration capacity, generated via inner shell electron drops.
• Gamma Rays: Shortest wavelength, highest frequency, highest energy photons.

Step 2: Order the specific options from lowest to highest energy. Extracting the four specific bands mentioned in the problem options:
• Radio waves $\rightarrow$ Lowest frequency profile $\rightarrow$ Lowest energy.
• Microwaves $\rightarrow$ Intermediate frequency, sits higher than radio waves.
• Infrared $\rightarrow$ High frequency band approaching visible light.
• X-rays $\rightarrow$ Extremely high frequency profile $\rightarrow$ Extremely high energy. Arranging them in a steady, increasing order of photon energy yields: \[ \text{Radio waves} < \text{Microwaves} < \text{Infrared} < \text{X-rays} \]