Physics - Sound Wave Question with Solution | TestHub

Following are expressions for four plane simple harmonic waves (i) $y_1=A\cos 2\pi \left(n_{1}t+\frac{x}{{\lambda }_1}\right)$ (ii) $y_2=A\cos 2\pi \left(n_{1}t+\frac{x}{{\lambda }_1}+\pi \right)$ (iii) $y_3=A\cos 2\pi \left(n_{2}t+\frac{x}{{\lambda }_2}\right)$ (iv) $y_4=A\cos 2\pi \left(n_{2}t-\frac{x}{{\lambda }_2}\right)$ The pairs of waves which will produce destructive interference and stationary waves respectively in a medium, are