Final answer:
Percussion over an area of atelectasis in the lungs would reveal dullness because atelectasis signifies a collapsed lung area with more solid tissue presence, resulting in a dull sound compared to the resonant sound in healthy lung tissue.
Step-by-step explanation:
When a nurse performs percussion over an area of atelectasis, the expected finding would be a dullness. Atelectasis refers to the partial or complete collapse of a part of the lungs, leading to a reduction in the air content in the alveoli. In such an area, where there is less air and more solid tissue, the percussion note would be duller compared to the normal lung areas which would typically produce a resonant sound due to the presence of air. Tympany, resonance, and hyperresonance are not characteristic percussion sounds associated with atelectasis. Tympany is typically heard over hollow organs such as the stomach when it is filled with gas, resonance is the normal finding in healthy lung tissue, and hyperresonance may be noted in cases of trapped air such as in pneumothorax or emphysema. Therefore, the correct answer to the nurse's question is a. dullness.