A string stretched between two fixed points sounds its second harmonic at frequency f.
Which expression, where n is an integer, gives the frequencies of harmonics that have a node at the centre of the string?
A. \(\frac{{n + 1}}{2}f\)
B. nf
C. 2nf
D. (2n + 1)f
Answer/Explanation
Markscheme
B
A ray of light passes from the air into a long glass plate of refractive index n at an angle θ to the edge of the plate.
The ray is incident on the internal surface of the glass plate and the refracted ray travels along the external surface of the plate.
What change to n and what change to θ will cause the ray to travel entirely within the plate after incidence?
Answer/Explanation
Markscheme
A
The diagram shows a second harmonic standing wave on a string fixed at both ends.
What is the phase difference, in rad, between the particle at X and the particle at Y?
A. 0
B. \(\frac{\pi }{4}\)
C. \(\frac{\pi }{2}\)
D. \(\frac{{3\pi }}{4}\)
Answer/Explanation
Markscheme
A
The graph shows the variation with position s of the displacement x of a wave undergoing simple harmonic motion (SHM).
What is the magnitude of the velocity at the displacements X, Y and Z?
Answer/Explanation
Markscheme
B
Which of the following is a correct comparison between standing waves and travelling waves?
Answer/Explanation
Markscheme
C
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