The absolute threshold for human vision is a candle flame seen from ______ kilometres on a dark,clear night.
A)30
B)40
C)50
D)60

Question

Quizplus · Accepted Answer

The absolute threshold for human vision is defined as the minimum amount of light that is needed to see an object. It is typically measured using a candle flame and the distance at which it can be seen on a dark, clear night. The average absolute threshold for human vision is about 1.5 to 3.0 candelas per square meter, which is approximately equal to the amount of light produced by a single candle flame seen from a distance of 50 kilometers on a clear, dark night. Therefore, the best choice is C) 50.

The Absolute Threshold for Human Vision Is a Candle Flame