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Question
A hospital uses an ultrasonic scanner to locate tumours in a tissue. What is the wavelength of sound in the tissue in which the speed of sound is 1.7 km s–1? The operating frequency of the scanner is 4.2 MHz.
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Solution 1
Speed of sound in the tissue, v = 1.7 km/s = 1.7 × 103 m/s
Operating frequency of the scanner, ν = 4.2 MHz = 4.2 × 106 Hz
The wavelength of sound in the tissue is given as:
`lambda = v/v`
`= (1.7 xx 10^3)/(4.2 xx 10^6) = 4.1 xx 10^(-4) m`
Solution 2
Here speed of sound => υ = 1.7 km s-1 = 1700 ms-1 and frequency υ= 4.2 MHz = 4.2 x 106 Hz
∴ Wavelength, A = υ/V = 1700/(4.2 x 106) =4.1 x 10-4 m.
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