Physics for IGCSE & O level - Waves And Sounds (Section 7 - No. 31)
What is the wavelength of the ultrasound if it has a frequency of 20 kHz, and the speed of sound is 1400 m/s in water?
0.07 m
70 m
28,000,000 m
7 m
คำอธิบาย
Wavelength = speed/frequency = 1400 m/s / 20000 Hz = 0.07 m.