The 'anti-noise' wave must have:

  1. twice the frequency of the noise
  2. the same frequency and amplitude as the noise but be 180^circ out of phase
  3. the same phase as the noise
  4. a much larger amplitude
Answer

B) the same frequency and amplitude as the noise but be 180^circ out of phase

So the waves cancel. SLO P-11-D-09 · Understanding

Physics MCQ · More Superposition, Stationary Waves and Beats MCQs · Practise