Article No. VK-PHY12
PHY12 Projection of Standing Waves
Projection of a standing ultrasonic wave in a liquid by means of divergent laser light
- Subject matter of the experiment
- Theoretical and practical aspects of the experiment
- Related Experiments
In the experiment a standing ultrasonic wave in a liquid is imaged by means of divergent laser light. The dependence of the brightness modulation of the projection images produced upon the wavelength of the light and the frequency of the ultrasonic wave is investigated and the sound velocity in the liquid (water) is determined.
Keywords: Sound wavelength, sound velocity, standing and travelling wave, divergent monochromatic light, refraction indices, focal length of an optical lens
The projection images of standing ultrasonic waves in water (here at 2.8 MHz, 3.5 MHz and 4.5 MHz) obtained with green and red laser light show the reduction of the spacing of the brightness maxima to be expected with increasing sound frequency. The difference between green and red laser is here caused by the wavelength dependence of the refraction indices.