Question 1: Ultrasound involves sound waves with frequencies higher than the upper audible limit of human hearing, typically above 20 kHz. These waves are used in medical imaging and industrial testing due to their ability to penetrate tissues and materials.

Answer: Ultrasound consists of high-frequency sound waves (above 20 kHz) used for imaging and testing because they can penetrate tissues and materials.

Question 1: Define ultrasound and explain how it differs from audible sound.

Answer: Ultrasound is sound with frequencies above 20 kHz, higher than what humans can hear, unlike audible sound which ranges from about 20 Hz to 20 kHz.

Question 2: Describe the mechanism by which ultrasound creates images in medical diagnostics.

Answer: Ultrasound waves reflect off internal structures; the reflected signals are received and processed to create images of organs and tissues.

Question 1: An ultrasound transducer emits waves at a frequency of 5 MHz. Calculate the wavelength of these waves in soft tissue where the speed of sound is approximately 1540 m/s. Use the formula: \( \lambda = \frac{v}{f} \).

Answer: Wavelength \( \lambda = \frac{1540 \text{ m/s}}{5,000,000 \text{ Hz}} = 0.000308 \text{ m} = 0.308 \text{ mm} \).

Question 2: A particular ultrasound wave has a wavelength of 0.5 mm in a material. If the speed of sound in that material is 1500 m/s, what is the frequency of the wave? Use the formula: \( f = \frac{v}{\lambda} \).

Answer: Frequency \( f = \frac{1500 \text{ m/s}}{0.0005 \text{ m}} = 3,000,000 \text{ Hz} = 3 \text{ MHz} \).

Question 1: Describe a simple experiment to measure the speed of ultrasound in a solid material. Include variables to control and safety precautions.

Answer: Use a pulse-echo method with a transducer attached to the material. Measure the time taken for the ultrasound to reflect back from a known distance. Variables include distance, temperature, and material type. Safety precautions involve handling equipment carefully to avoid damage and ensuring the device operates within safe limits.

Question 1: An ultrasound scan shows that the echo from a tissue boundary arrives 13 microseconds after emission. If the speed of sound in tissue is 1540 m/s, estimate the distance to the boundary.

Answer: Distance \( d = \frac{v \times t}{2} = \frac{1540 \text{ m/s} \times 13 \times 10^{-6} \text{ s}}{2} = 0.01001 \text{ m} = 10.01 \text{ mm} \).

Question 1: Explain how ultrasound technology is used in non-destructive testing of materials such as metals and plastics.

Answer: Ultrasound is used to detect internal flaws or cracks in materials by sending waves through the material and analyzing the reflections to identify defects without damaging the object.

Question 1: Write a brief paragraph on the importance of ultrasound in medicine and industry.

Answer: Ultrasound is crucial in medicine for imaging internal organs, monitoring pregnancies, and diagnosing conditions without invasive procedures. In industry, it helps detect flaws in materials, ensure quality control, and improve safety by non-destructive testing.