This diagram shows how loud certain frequencies must be in
order for people of different ages to hear them. the needed
intensity is called the "hearing level."
according to the graph, what is the maximum age at which a
4000 hz sound wave with an intensity of 20 db would be
heard?
hearing level (db)
55
60
65
70
500 hz
2000 hz
3,000 hz
4,000 hz
6,000 hz
70
20
30
60
40 50
age (years)
age (years)