COMEDK2014PhysicsWaves and Sound
A hospital uses an ultrasonic scanner to locate tumors in a tissue. The operating frequency of the scanner is 4.2 MHz . The speed of sound in a tissue is 1.7 ~km ~s ⁻¹ . The wavelength of sound in the tissue is
Options
- A4 10⁻³ ~m
- B8 10⁻³ ~m
- C4 10⁻⁴ ~m
- D8 10⁻⁴ ~m
Correct answer
C. 4 10⁻⁴ ~m
Step-by-step solution
Given, frequency, f=4.2 MHz =4.2 10⁶ ~Hz Velocity of sound, v=1.7 kms ⁻¹=1.7 10³ ~ms ⁻¹ The wavelength of sound in the tissue is given as aligned &= v f (v=f ) &= 1.7 10³ 4.2 10⁶ =4 10⁻⁴ ~m aligned