The correct answer is 400 nm to 700 nm. Explanation & Key Takeaways: • The visible light is a part of the electromagnetic spectrum that can be detected by the human eye. • The wavelength of visible light ranges from 400 nanometers (nm) to 700 nanometers (nm). • 400 nm corresponds to violet light, while 700 nm corresponds to red light. • Visible light is responsible for the colours we see in the natural world and is essential for processes like photosynthesis. Important Notes: • The electromagnetic spectrum is divided into several regions based on wavelength or frequency. These include radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. • The visible spectrum is a very narrow part of the electromagnetic spectrum, but it is the most significant to humans because it is directly detectable by the human eye. • Wavelength is inversely proportional to frequency. This means that shorter wavelengths (e.g., violet light) have higher frequencies, while longer wavelengths (e.g., red light) have lower frequencies.