Question

Eye is most sensitive to

• A. 20 $\mathring{A}$ light
• B. 1000 $\mathring{A}$ light
• C. 5000 $\mathring{A}$ light
• D. 7000 $\mathring{A}$ light

Answer 1

Answer: (C)

5000 $\mathring{A}$ light

At extremely low intensities of stimuli, when only rods are stimulated, the retina shows a variable sensitivity to light according to its wavelength, being most sensitive at about 5000 angstroms, the absorption maximum of the rod visual pigment, rhodopsin. There is a characteristic shift in the maximum sensitivity from 5000 angstroms for scotopic (night) vision to 5550 angstroms for photopic (day) vision, called Purkinje shift.