A person has entered N3 sleep when delta waves account for _____ percent or more of brain wave activity.

• A. 5
• B. 20
• C. 75
• D. 90

Answer: (B)

Verified step by step guidance

1. Understand the stages of sleep: Sleep is divided into several stages, including NREM (Non-Rapid Eye Movement) and REM (Rapid Eye Movement) sleep. NREM sleep is further divided into stages N1, N2, and N3.
2. Identify the characteristics of N3 sleep: N3 sleep, also known as slow-wave sleep or deep sleep, is characterized by the presence of delta waves, which are high amplitude, low frequency brain waves.
3. Recognize the significance of delta waves: Delta waves are most prominent during N3 sleep and are associated with the deepest stages of sleep, where the body is in a state of restoration and recovery.
4. Determine the threshold for N3 sleep: N3 sleep is defined by the presence of delta waves accounting for a certain percentage of brain wave activity. This threshold is crucial for identifying when a person has entered this stage of sleep.
5. Apply the knowledge to the problem: Use the information about delta wave activity to determine the percentage required for a person to be considered in N3 sleep, which is when delta waves account for 20 percent or more of brain wave activity.