Answer:
(C) 6.2 cm
Explanation:
We are given that
Frequency of ultra sound,f=5.0 MHz=[tex]5\times 10^6 Hz[/tex]
By using [tex]1MHz=10^6 Hz[/tex]
We know that speed of sound in human tissue,v=1540m/s
Let [tex]\lambda[/tex] be the wavelength of ultrasound .
Then, depth of penetration of ultrasound=[tex]d=200\lambda[/tex]
We have to find the approximate depth of penetration of ultrasound.
We know that
[tex]\lambda=\frac{v}{f}[/tex]
Using the formula
[tex]d=200\times \frac{v}{f}=200\times \frac{1540}{5\times 10^6}[/tex]
[tex]d=6.2\times 10^{-2} m[/tex]
[tex]d=6.2\times 10^{-2}\times 10^2=6.2\times 10^{-2+2}=6.2\times 10^0=6.2\times 1=6.2 cm[/tex]
By using [tex]a^x\cdot a^y=a^{x+y}[/tex]
[tex]10^0=1[/tex]
Option C is true.
