Physics
Wave interference and optics
- 1.
A travelling wave has frequency 250 Hz and wavelength 1.20 m. Find its speed and period, to 3 significant figures.
[3 marks] - 2.
Two points on a progressive wave are separated by 0.150 m along propagation. Wavelength is 0.600 m. Find the phase difference in radians and explain whether they are in antiphase.
[3 marks] · no calculator - 3.
A string fixed at both ends has length 0.800 m, tension 64.0 N and mass per length 0.0100 kg m^-1. Find its third-harmonic frequency and the number of antinodes. Assume uniform tension.
[3 marks] - 4.
Coherent 600 nm light passes through slits 0.300 mm apart onto a screen 2.00 m away. Find fringe spacing and state the approximation and coherence requirement used.
[3 marks] - 5.
A grating has 500 lines per mm. Monochromatic light of wavelength 650 nm falls normally on it. Find the second-order diffraction angle and greatest possible order, to 3 significant figures where appropriate.
[3 marks] - 6.
Unpolarised light of intensity 80.0 W m^-2 passes through ideal polarisers with axes at 0, 30 and 90 degrees to a fixed reference. Find the final intensity and compare with removing the middle polariser.
[3 marks]
Marking points are indicative, not an official mark scheme. Accept equivalent valid methods and supported interpretations that address the task; award each mark once without requiring the model wording.