Sure! To understand why infrared rays are said to be longer than visible light waves but have less energy, let's first explore the properties of electromagnetic waves.
Electromagnetic waves are a form of energy that can travel through space in the form of oscillating electric and magnetic fields. They can be categorized based on their wavelengths and frequencies.
Wavelength: The wavelength of an electromagnetic wave is the distance between two consecutive points in the wave that are in phase (e.g., peak to peak or trough to trough). It is usually measured in meters, centimeters, or nanometers, depending on the wave's frequency.
Frequency: The frequency of an electromagnetic wave is the number of complete oscillations (cycles) it undergoes in one second. It is measured in Hertz (Hz), which represents cycles per second.
Now, let's look at why infrared rays are considered longer but less energetic than visible light waves:
Wavelength: Infrared rays have longer wavelengths than visible light waves. Visible light ranges from approximately 400 to 700 nanometers (nm), with violet having the shortest wavelength and red having the longest. Infrared rays, on the other hand, have wavelengths longer than those of red light, typically starting from around 700 nm and extending to several micrometers (μm).
Energy: The energy of an electromagnetic wave is directly proportional to its frequency and inversely proportional to its wavelength. This relationship is described by the equation E = h * f, where E is the energy of the wave, h is Planck's constant (a fundamental constant in quantum mechanics), and f is the frequency of the wave.
Since infrared rays have longer wavelengths than visible light waves, their frequencies are lower. As a result, according to the equation E = h * f, the energy carried by infrared rays is lower than that of visible light waves.
To summarize, infrared rays are considered longer than visible light waves because they have longer wavelengths. However, they have less energy because their lower frequencies, which are inversely related to wavelength, lead to lower energy levels according to the equation E = h * f. This energy difference is why infrared radiation is often used for non-visible applications, such as thermal imaging and remote controls, while visible light is used for vision and various other everyday applications.