Question

The time periods of three sound waves A, B and C
are 0.2 ms, 0.2 s and 3 s respectively. The inaudible
sound waves are
(1) A and B
(2) B and C
(3) A and C
(4) A, B and C
​

Answer 1

Answer:

F=1/T

so all three are inaudible

Answer 2

Answer:

i think the correct answer is (4) A,B,C