Which color do long-wavelength cones respond to?

Which color do long-wavelength cones respond to?

• A. Red
• B. Green
• C. Blue
• D. Yellow

Answer: (A)

Long-wavelength cones, the L-type, are most sensitive to light at the red end of the spectrum. Their peak response sits in the long-wavelength range, so red light activates them most strongly. Green light mainly stimulates the middle-wavelength cones, and blue light stimulates the short-wavelength cones. Yellow perception arises from a mix of red and green signals, not from the long-wavelength cones alone. So the color these cones respond to most directly is red.

Long-wavelength cones, the L-type, are most sensitive to light at the red end of the spectrum. Their peak response sits in the long-wavelength range, so red light activates them most strongly. Green light mainly stimulates the middle-wavelength cones, and blue light stimulates the short-wavelength cones. Yellow perception arises from a mix of red and green signals, not from the long-wavelength cones alone. So the color these cones respond to most directly is red.