Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

Which color of visible light has the longest wavelength?

1. Blue

2. Green

3. Red

4. Violet

The correct answer is: Red

The color of visible light that has the longest wavelength is red. In the visible spectrum, wavelengths decrease in length as you move from red at one end to violet at the other end. Red light has wavelengths that range from approximately 620 to 750 nanometers, while other colors have shorter wavelengths: blue light typically ranges from around 450 to 495 nanometers, green from about 495 to 570 nanometers, and violet from about 380 to 450 nanometers. The relationship between wavelength and color is essential in understanding the electromagnetic spectrum. Longer wavelengths correspond to lower energy levels, which is why red is situated at the opposite end from violet, which has the highest energy and the shortest wavelength in the visible spectrum.