Final answer:
For an individual with a 20% just-noticeable difference in the ability to perceive heat, the only pair of peppers that would have the same perceived spiciness is 100 SHU and 120 SHU.
Step-by-step explanation:
In peppers, spicy heat is rated in Scoville Heat Units (SHUs), where 0 is the least amount of spicy heat. If the just-noticeable difference (JND) in the ability to perceive a difference in heat detection for an individual is 20%, we need to determine which pair of peppers would have the same perceived spiciness for this person. To calculate this, we multiply the heat unit of the milder pepper by 1.20 (which is the same as adding 20% to the value) to see if the result matches the hotter pepper's SHU value.
- a) 100 SHU × 1.20 = 120 SHU
- b) 500 SHU × 1.20 = 600 SHU (not 520 SHU)
- c) 1000 SHU × 1.20 = 1200 SHU (not 1100 SHU)
- d) 2000 SHU × 1.20 = 2400 SHU (not 2040 SHU)
Based on the above calculations, the only pair of peppers that would have the same perceived spiciness for this person is a) 100 SHU and 120 SHU.
Peppers contain capsaicin, which opens the same sodium channels as warm receptors, leading to the sensation of spiciness. Different individuals might have a different JND, accounting for why some find peppers to be less painful than others, as their tolerance for heat affects the perception of pain.