Date | November 2021 | Marks available | 3 | Reference code | 21N.2.HL.TZ0.2 |
Level | Higher level | Paper | Paper 2 | Time zone | 0 - no time zone |
Command term | Determine | Question number | 2 | Adapted from | N/A |
Question
A longitudinal wave travels in a medium with speed 340 m s−1. The graph shows the variation with time t of the displacement x of a particle P in the medium. Positive displacements on the graph correspond to displacements to the right for particle P.
Another wave travels in the medium. The graph shows the variation with time t of the displacement of each wave at the position of P.
A standing sound wave is established in a tube that is closed at one end and open at the other end. The period of the wave is . The diagram represents the standing wave at and at . The wavelength of the wave is 1.20 m. Positive displacements mean displacements to the right.
Calculate the wavelength of the wave.
Determine, for particle P, the magnitude and direction of the acceleration at t = 2.0 m s.
State the phase difference between the two waves.
Identify a time at which the displacement of P is zero.
Estimate the amplitude of the resultant wave.
Calculate the length of the tube.
A particle in the tube has its equilibrium position at the open end of the tube.
State and explain the direction of the velocity of this particle at time .
Draw on the diagram the standing wave at time .
Markscheme
«s» or «Hz» ✓
«m» ✓
Allow ECF from MP1.
Award [2] for a bald correct answer.
OR «s−1» ✓
«ms−2» ✓
«opposite to displacement so» to the right ✓
«±» OR ✓
1.5 «ms» ✓
8.0 OR 8.5 «μm» ✓
From the graph on the paper, value is 8.0. From the calculated correct trig functions, value is 8.49.
L = «» 0.90 «m» ✓
to the right ✓
displacement is getting less negative
OR
change of displacement is positive ✓
horizontal line drawn at the equilibrium position ✓