Please clarify the following questions for me:
1. A hospital uses an ultrasonic scanner to locate tumours in a tissue. The operating frequency of the scanner is 4.2MHz. The speed of sound in the tissue is 1.7 kms/s. Find the wavelength of the sound in the tissue.
2. In medium, sound travels 2 km in 3 sec and in air it travels 3 km in 10 sec. Find the ratio of the wavelengths of sound in the two mediums.
3. If velocity of sound in a gas is 360 m/s and the distance between a compression and the nearest rarefaction is 1 m, then find the frequency of the sound.

Question

anonymous · Answer

1 Speed = wavelength * frequency. So 0.4mm
2 Wavelength is proportional to speed. So ratio of wavelengths is same as the ratio of speeds. 
3 Speed = wavelength * frequency. Wavelength is 2m. So 180Hz