Question

Which colour of the light has the longest wavelength?

• A. red
• B. blue
• C. green
• D. violet

Answer 1

The Correct Option is A

To determine which color of light has the longest wavelength, let's review the visible light spectrum. The visible light spectrum is a part of the electromagnetic spectrum that is visible to the human eye and falls within the wavelength range of approximately 380 nm to 750 nm.

The colors of the visible spectrum in order of increasing wavelength are:

• Violet (around 380-450 nm)
• Blue (around 450-495 nm)
• Green (around 495-570 nm)
• Yellow (around 570-590 nm)
• Orange (around 590-620 nm)
• Red (around 620-750 nm)

From this list, it is clear that red light has the longest wavelength among the colors given in the options.

This property of red light having a longer wavelength is why it is often used in applications like traffic signals and stop signs, as it is visible from a greater distance. The longer wavelength makes it scatter less, allowing it to travel further.

Thus, the correct answer is red.