Answer the following about sound.

The diagram shows a builder hitting a wall with a hammer. Two children, X and Y, are standing the same distance from the builder, but on different sides of the wall.

1. aHow does the sound produced change when the frequency of the sound wave increases? [1]
2. bHow does the sound produced change when the amplitude of the sound wave decreases? [1]
3. cWho of the two children is likely to hear the sound of the hammer first? [1]
4. dExplain your answer. [1]

You'll mark your own answer against the marking guide when you hand it in.