A progressive wave travelling along the positive \(x\)-direction is represented by \(y(x,t)=A\sin(kx-\omega t+\phi)\). Its snapshot at \(t=0\) is given in the figure.

         
For this wave, the phase \(\phi\) is:
1. \(\frac{\pi}{2}\)
2. \(\pi\)
3. \(0\)
4. \(-\frac{\pi}{2}\)

For a transverse wave travelling along a straight line, the distance between two peaks (crests) is \(5~\text{m}\), while the distance between one crest and one trough is \(1.5~\text{m}\). The possible wavelengths (in m) of the waves are:
1. \(1,2,3, \dots\)
2. \(\frac{1}{1},\frac{1}{3},\frac{1}{5},\dots\)
3. \(\frac{1}{2},\frac{1}{4},\frac{1}{6},\dots\)
4. \(1,3,5, \dots\)

Which, of the following equation represents a travelling wave?
1. \(y=A\sin(15x-2t)\)
2. \(y=Ae^{-x^2}(vt+\theta)\)
3. \(y=Ae^{x}\cos (\omega t-\theta)\)
4. \(y=A\sin x \cos \omega t\)