Wave Motion Ques 110
- At $x=0$ how many times the amplitude of $y _1+y _2$ is zero in one second?
(2006, 5M)
(a) 192
(b) 48
(c) 100
(d) 96
Show Answer
Answer:
Correct Answer: 110.(c)
Solution:
- At $x=0, y=y _1+y _2=2 A \cos 96 \pi t \cos 4 \pi t$
Frequency of $\cos (96 \pi t)$ function is $48 Hz$ and that of $\cos (4 \pi t)$ function is $2 Hz$.
In one second, cos function becomes zero at $2 f$ times, where $f$ is the frequency. Therefore, first function will become zero at 96 times and the second at 4 times. But second will not overlap with first. Hence, net $y$ will become zero 100 times in $1 s$.
BETA
