Waves · Question 54

Two waves having equation x1 = a ( t - kx + 1), x2 = a ( t - kx + 2). If in the resultant wave the frequency and amplitude remain equal to amplitude of superimposing waves, the phase difference between them is

1. 6
2. 2 3
3. 4
4. 3

If the tension and diameter of a sonometer wire of fundamental frequency n is doubled and density is halved then its fundamental frequency will become

1. n4
2. 2n
3. n
4. n 2

A string is cut into three parts, having fundamental frequencies n1, n2, n3 respectively. Then original fundamental frequency n related by the expression as

1. 1n = 1n1 + 1n2 + 1n3
2. n = n1 n2 n3
3. n = n1 + n2 + n3
4. n = n1 + n2 + n33

Two stationary sources each emit waves of wavelength . An observer moves from one source to the other with velocity u. Then the number of beats heard by him is

1. 2u
2. u
3. u
4. u2