# Ultrasonic Waves of Frequency 4.5 Mhz Are Used to Detect Tumour in Soft Tissue. the Speed of Sound in Tissue is 1.5 Km S−1 and that in Air is 340 M S−1 - Physics

Sum

Ultrasonic waves of frequency 4.5 MHz are used to detect tumour in soft tissue. The speed of sound in tissue is 1.5 km s−1 and that in air is 340 m s−1. Find the wavelength of this ultrasonic wave in air and in tissue.

#### Solution

(a) Given:
Frequency of ultrasonic wave f = 4.5 MHz = 4.5 × 106 Hz
Velocity of air = 340 m/s
Speed of sound in tissue = 1.5 km/s
Wavelength λ = ?
As we know, $v = f\lambda$

$\therefore \lambda = \frac{340}{4 . 5 \times {10}^6}$

$\Rightarrow \lambda = 7 . 6 \times {10}^{- 5} m$

(b)   Velocity of sound in tissue vtissue= 1500 m/s

$\lambda = \frac{v_{tissue}}{f}$

$\Rightarrow \lambda = \frac{1500}{4 . 5 \times {10}^{- 6}} \text{ m }$

$\Rightarrow \lambda = 3 . 3 \times {10}^{- 4} \text{ m }$

Concept: Wave Motion
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#### APPEARS IN

HC Verma Class 11, 12 Concepts of Physics 1
Chapter 16 Sound Waves
Q 7 | Page 353