1. Multiple Choice: What principle of ultrasound physics is primarily responsible for the image resolution? a) Piezoelectric effect b) Doppler effect c) Attenuation d) Reflection Correct Answer: d) Reflection Rationale: The reflection of the ultrasound waves off of different tissues creates the image, with varying degrees of brightness corresponding to the tissue density. 2. Fill-in-the-Blank: The _______ control adjusts the brightness of the ultrasound image. Correct Answer: Gain Rationale: The gain control amplifies the electrical signals received from the returning ultrasound waves, thereby adjusting the brightness of the image.