Answer :
(a) [tex]7.62 \times 10^{-5} m[/tex] is the wavelength in air of such a sound wave.
(b) [tex]3.33 \times 10^{-4}\ m[/tex] is the wavelength of this wave in tissue.
Explanation:
Frequency and wavelength can be related by the equation,
Velocity = Wavelength x Frequency
[tex]v=\lambda \times f[/tex]
where,
v - velocity of light for all EM (electromagnetic) waves in vacuum
Given:
f - 4.50 MHz = [tex]4.50 \times 10^{6} \mathrm{Hz}[/tex]
a) To find the wavelength in air
We know,
Speed of sound in air = 343 m/s
Apply given frequency and speed of sound in air, we get
[tex]\lambda=\frac{v}{f}=\frac{343}{4.5 \times 10^{6}}=76.2 \times 10^{-6}=7.62 \times 10^{-5}\ \mathrm{m}[/tex]
b) If the speed of sound in tissue is 1500 m/s, find the wavelength of this wave in tissue
Speed of sound in tissue, v = 1500 m/s
[tex]\lambda=\frac{v}{f}=\frac{1500}{4.5 \times 10^{6}}=333.33 \times 10^{-6}=3.33 \times 10^{-4} \mathrm{m}[/tex]