Correct option 1. (A) 2. (A) 200m/s 3. (D) 96
Explanation:
1. In one second number of maximas is called the beat frequency.
2. (A) Speed of wave v = ω/K
3. At x = 0, y = y1 + y2 = 2A cos 96πt cos 4 πt Frequency of cos (96 πt) function is 45 Hz and that of cos (4πt) function is 2Hz.
In one second, cos function becomes zero at 2f 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 1s.