PROCEDURE:The spectrometer is adjusted to a distant object to catch the distant object very clearly. The spectrometer is now placed in front of a sodium vapor lamp and the slit is illuminated. The collimator is adjusted to set the clear slit image. The telescope is brought in line with the collimator, and the slit image is seen through the back drop of cross wire. The aqua grating setup is fitted to the prism table and the glass vessel is filled with distilled water. The quartz crystal is immersed in the distilled water with its plane perpendicular to the incident light through the collimator. The transmitter output is connected to the crystal and the frequency knob of the sine wave transmitter is adjusted by viewing through the telescope until the slit images splits to give number of fine lines. The central slit image, first order spectral line on left and first order spectral line on the right, are identified in the observed spectrum. Spectrometer readings are noted for spectral lines present at left (qL) and right (qR) hand side. Wave length and velocity of the ultrasonic wave is calculated using Eqn.(3) and (4).
The velocity of ultrasonic waves in the given liquid = ……………m/s