Two waves executing simple harmonic motion travelling in the same direction with same amplitude and frequency are superimposed. The resultant amplitude is equal to the 3 times of amplitude of individual motions. The phase difference between the two motions is _____ (degree)

Step-by-step solution

When two waves of the same frequency superimpose, the resultant amplitude is given by A resultant   = A 1 2 + A 2 2 + 2 A 1 A 2 cos ϕ ⇒ 3   A = A 2 + A 2 + 2 A 2 cos ϕ ⇒ 3 A 2 = 2 A 2 + 2 A 2 cos ϕ ⇒ cos ϕ = 1 2 ∴ ϕ = 60 ° ∴ Phase difference = 60 degree