If resultant wave of two waves, each of amplitude A is also A then, phase difference between those two waves is

If resultant wave of two waves, each of amplitude A is also A then, ph

1.	If resultant wave of two waves, each of amplitude A is also A then, phase difference between those two waves is
Answer» `60^(@)` `90^(@)` `120^(@)` `180^(@)` Solution :Ifamplitude of rresultant wave DUE to supeerpositon of two waves with amplitudes `A _(1) and A_(2)` with PHASE difference `del,` is A. then we have `A .= sqrt (A _(1) ^(2) + A _(2) ^(2) + 2 A _(1) A _(2) COS delta)` ` therefore A^(.2)= A _(1) ^(2) + A _(2) ^(2) + 2 A_(1) A _(2) cos delta ` But here, ` A_(1) = A _(2) =A. =A` (suppose) and so: `A ^(2) = 2A ^(2) + 2 A ^(2)cos delta ` `therefore A ^(2) =2A ^(2) (1 + cos delta )` `therefore 1/2 =1 + cos delta ` `therefore cos delta =-1/2` `therefore delta = 120^(@) (becausecos 120 ^(@) =-(1)/(2))`