Physics 9702 · AS & A Level · Progressive waves

Progressive waves — practice question

At a fixed point P, progressive sound waves Y and Z meet. Figure 4.1 shows how the displacement $x$ of each wave at P changes with time $t$.
(a(i))[1]

From Fig. 4.1, state one wave quantity that is identical for Y and Z.

(a(ii))[1]

From Fig. 4.1, state one wave quantity that is different for Y and Z.

(b)[1]

State and explain if waves Y and Z are coherent.

(c)[1]

Determine the phase difference separating the waves.

(d)[1]

At P, the two waves superpose. Use Fig. 4.1 to determine the resultant displacement when $t = 0.75\,\text{ms}$.

(e)[2]

The intensity of wave Y at point P is $I$. Determine, in terms of $I$, the intensity of wave Z.

(f)[3]

The speed of wave Z is $330\,\text{m s}^{-1}$. Determine the wavelength of wave Z.

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