Final answer:
When awake but tired with eyes closed, an EEG shows theta waves.
Step-by-step explanation:
When awake but tired, with eyes closed, an EEG would show theta waves. Theta waves are low frequency (4-7 Hz) and higher in amplitude than the alpha waves observed during the early part of sleep. Although they are characteristic of stage 1 sleep, theta waves can also be seen when someone is awake but tired.