Statement: In human eye, there are 3 types of cones which possess their own characteristic photopigment that respond to red, green and blue lights.
Explanation: When these cones are stimulated equally a sensation of white light is produced.

Question

Statement: In human eye, there are 3 types of cones which possess their own characteristic photopigment that respond to red, green and blue lights. 
Explanation: When these cones are stimulated equally a sensation of white light is produced.

Accepted Answer

The correct option is 1: Statement and Explanation are true.

The human visual system is a classic example of **trichromatic theory**, which is based on the existence of three types of cone photoreceptor cells in the retina. The **Statement** correctly describes this fundamental biological fact. Each type of cone contains a different photopigment (iodopsin) that absorbs light most efficiently at a specific wavelength range, corresponding roughly to Short-wavelength (S-cones, peaking at blue), Medium-wavelength (M-cones, peaking at green), and Long-wavelength (L-cones, peaking at yellow/red). The perception of all the thousands of colors we see is a result of the brain interpreting the *ratio* of stimulation across these three cone types. For instance, if S-cones are minimally stimulated and L-cones are highly stimulated, the brain perceives red. The **Explanation** logically follows the principles of additive color mixing. In the realm of light, when the three primary colors (red, green, and blue) are mixed in roughly equal physical proportions, the resultant light is perceived as white. Physiologically, this happens when light of all visible wavelengths reaches the retina in a way that provides approximately equal stimulation to all three cone types. The equal, simultaneous firing of S, M, and L cones is the neurological signal that the brain translates into the sensation of white light, making the Explanation a correct and conceptually linked fact to the Statement.

The incorrect option is 2: Statement is true but Explanation is wrong.

This option is incorrect because the Explanation is a correct principle of human color perception. If the Statement establishes the existence of three primary color receptors (cones), the Explanation correctly describes what happens when all three are equally activated. The equal stimulation of red, green, and blue light receptors results in the perception of white light, an application of the additive color mixing model directly within the retina. Therefore, classifying the Explanation as wrong contradicts established scientific fact regarding human vision.

The incorrect option is 3: Statement and Explanation both are wrong.

This option is fundamentally incorrect as both components are accurate descriptions of the human visual system. The presence of three cone types is the basis for trichromatic vision, a universally accepted fact in biology and optics. Furthermore, the concept of equal stimulation of these three types resulting in a white light sensation is a direct corollary of this trichromacy and the nature of additive color mixing. Dismissing both the Statement and the Explanation as entirely wrong would be to deny a core mechanism of human biology.

The incorrect option is 4: Statement is wrong for human eye.

The Statement is accurate for the human eye, making this option incorrect. Humans are physiologically defined as *trichromats* because our retinas possess three distinct types of cone cells (S, M, L) responsible for detecting the wavelengths corresponding to blue, green, and red regions of the spectrum. This is the physiological basis of all color vision. Therefore, claiming that the Statement is wrong for the human eye is factually false and misrepresents the structure of the retina.