Question

  Explain why it is possible to observe sound interference effects using two whistles, but not light

interference effects using two lamps, even if the dimensions of the apparatus are suitably modified.

Answer 1

Because the whistle emits sounds of certain frequencies and, consequently, wavelengths, which is a condition for the interference. Lamps, however, emit light of different wavelengths and even if interference occurs between some waves of appropriate length, other waves of different length will not let us observe it.