If we go longer in wavelength and lower in frequency than red we get what?

If we go longer in wavelength and lower in frequency than red we get what?

• A. Ultraviolet
• B. X-ray
• C. Infrared
• D. Microwave

Answer: (C)

When wavelength increases, frequency decreases (the speed of light is constant: f = c/λ). Red light is the last part of the visible spectrum, with wavelengths around 700 nm. Going longer than red places you in infrared radiation, which has longer wavelengths and lower frequencies than red. Ultraviolet and X-ray have shorter wavelengths and higher frequencies, so they don’t fit. Microwave also has longer wavelengths, but it sits beyond infrared, farther along the spectrum. The closest and most direct match to the description is infrared.

When wavelength increases, frequency decreases (the speed of light is constant: f = c/λ). Red light is the last part of the visible spectrum, with wavelengths around 700 nm. Going longer than red places you in infrared radiation, which has longer wavelengths and lower frequencies than red. Ultraviolet and X-ray have shorter wavelengths and higher frequencies, so they don’t fit. Microwave also has longer wavelengths, but it sits beyond infrared, farther along the spectrum. The closest and most direct match to the description is infrared.