Two waves are described by: y1 = 6 cos 180t and y2 = 6 cos 186t, (both in metres).What effective frequency does the resultant vibration have at a point?
A)92 Hz
B)183 Hz
C)6 Hz
D)3 Hz
E)366 Hz

Question

Quizplus · Accepted Answer

The effective frequency of the resultant vibration is the average of the frequencies of the two waves. 
Frequency of y1 = 180 Hz 
Frequency of y2 = 186 Hz 
Average frequency = (180 Hz + 186 Hz) / 2 = 183 Hz. 
Therefore, the answer is B) 183 Hz.

Two Waves Are Described By: Y1 = 6 Cos 180t