1. 1
   A student drops a pebble into a still pond and watches ripples spread out across the surface of the water in circles.

   (a)

   Water waves such as these are best classified as which type of wave?

   [1 mark]

   • ALongitudinal, because the water oscillates parallel to the direction the ripples travel
   • BTransverse, because the water oscillates perpendicular to the direction the ripples travel
   • CLongitudinal, because the water itself moves outward with the ripple
   • DTransverse, because the ripple only travels at the exact centre of the pond

   (b)

   A small leaf floating on the pond bobs up and down as each ripple passes beneath it, but does not move outward with the ripple. What does this tell us about what a wave transfers?

   [1 mark]

   • AA wave transfers energy and information without transferring matter
   • BA wave transfers matter from one place to another
   • CA wave transfers only matter, not energy
   • DA wave transfers neither energy nor matter

   (c)

   The student notices that the ripples closest to where the pebble landed are taller than the ripples further away, but the distance between neighbouring wave crests stays the same everywhere. Using the correct wave terms, explain what these two observations describe.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Seismologists studying an earthquake detect two types of seismic waves travelling through the rock of the Earth's crust: P-waves, in which particles of rock oscillate back and forth in the same direction the wave travels, and S-waves, in which particles oscillate from side to side, perpendicular to the direction of travel.

   (a)

   Which type of wave are the P-waves?

   [1 mark]

   • ATransverse waves
   • BStanding waves only, not travelling waves
   • CElectromagnetic waves
   • DLongitudinal waves

   (b)

   As the seismic waves travel from one type of rock layer into a denser rock layer, their speed and direction of travel change. What is this change called?

   [1 mark]

   • ADiffraction
   • BReflection
   • CRefraction
   • DAbsorption

   (c)

   Explain, in terms of wave properties, why seismic waves change direction when they cross the boundary between two rock layers of different density, and explain what happens to a wave when it reaches a boundary but is not transmitted into the new material.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A harbour engineer stands on a breakwater and counts sea waves passing a fixed marker post. She counts 8 wave crests passing the post every 20 seconds. She also measures that the distance between two neighbouring wave crests is 5 m.

   (a)

   Calculate the frequency of the waves, and state what is meant by the period of a wave.

   [3 marks]

   (b)

   Calculate the speed of the sea waves, and explain why a swimmer floating nearby bobs up and down as the waves pass but is not carried along the coast by the waves.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   In a physics lesson from many decades ago, a teacher demonstrated wave behaviour using two classic pieces of apparatus: a long stretched spring (a 'slinky'), which could be shaken from side to side or pushed and pulled along its length, and a ripple tank of water, used to show waves passing through a narrow gap in a barrier.

   (a)

   Explain, using the slinky spring, the difference between how a transverse wave and a longitudinal wave transfer energy through a medium.

   [6 marks]

   (b)

   Using the ripple tank, the teacher showed water waves reaching a narrow gap in a barrier and spreading out into the space beyond it. Explain what is happening to the waves in this demonstration, and explain how the width of the gap compared with the wavelength of the waves affects how much the waves spread out.

   [6 marks]

   Total for question 4: 12 marks

End of questions