Question

A yellow LED light emits light with a single wavelength of $570Snm. A red filter, when held up to a broad-spectrum white flashlight, makes the light from that flashlight look deep red. What color will the yellow LED appear when viewed through that red filter? (pick the best choice)

Select the correct answer
O bright green
O bright red
O mostly black
O bright yellow

Answer 1

The yellow LED will appear bright red when viewed through the red filter.

Step-by-step explanation:

When white light passes through or is reflected by a colored substance, a characteristic portion of the mixed wavelengths is absorbed. The remaining light will then assume the complementary color to the wavelength(s) absorbed. In this case, the red filter absorbs blue and green light, allowing only red light to pass through.

Since the yellow LED emits light with a single wavelength of $570Snm, and the red filter only allows red light to pass through, the yellow LED will appear bright red when viewed through the red filter.

Therefore, the correct answer is bright red.