Final answer:
The normal interval time for the QT interval is 0.33-0.42 second. It represents the time it takes for the ventricles to depolarize and repolarize and is measured on an electrocardiogram (ECG). A normal QT interval indicates a healthy electrical conduction in the heart.
Step-by-step explanation:
The normal interval time for the QT interval is 0.33-0.42 second. The QT interval is a segment on an electrocardiogram (ECG) that represents the time it takes for the ventricles to depolarize and repolarize. It measures from the beginning of the QRS complex to the end of the T wave. A QT interval within the normal range indicates a healthy electrical conduction in the heart.