Stimuli, both internal and external, are detected and lead to a response (A-level only)

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Question 12
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Figure 3 shows the wavelengths of light absorbed by three types of photoreceptor found in the human retina.

A line graph showing the percentage of maximum light absorption against wavelength in nanometers (nm) for three types of photoreceptor in the human retina: blue-sensitive, green-sensitive, and red-sensitive. The wavelength scale on the horizontal axis runs from 400 nm to 700 nm, with major markings every 100 nm and grid lines every 10 nm. The vertical axis represents light absorption as a percentage of maximum, with scale markings at 0, 25, 50, 75, and 100, and grid lines every 5%. The blue-sensitive photoreceptors have a peak of 100% absorption at approximately 430 nm, and absorption falls to 0% at about 530 nm. The green-sensitive photoreceptors have their peak at approximately 535 nm, and absorption falls to 0% at about 650 nm. The red-sensitive photoreceptors have their peak at approximately 570 nm, and absorption falls to 0% at about 700 nm. At 480 nm, light absorption is about 55% for blue-sensitive cones, 65% for green-sensitive cones, and 20% for red-sensitive cones.

Use Figure 3 and your knowledge of colour vision to explain how a blue-green colour is seen at 480 nm.

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Stimuli, both internal and external, are detected and lead to a response (A-level only) Questions

  1. A Level
  2. /Biology
  3. /Stimuli, both internal and external, are detected and lead to a response (A-level only)