Four harmonic waves of equal freuencies and equal intensity `I_(0)` have phase angles `0, (pi)/(3), (2pi)/(3)` and `pi`. When they are superposed, the intensity of the resulting wave is `nI_(0)`. The value of `n` is

Answer

`3`

Explanation

Let amplitude of individual wave is A then by using phasor method

So resultant amplitude `A_(r)^(2)`
`= A^(2)+A^(2)+2a^(2)cos60`
`:. A_(r)^(2)=3A^(2)`
`:. I_(r)=3I_(0)`.