Answer:
The correct answer is 1. EEG.
EEG or electroencephalography is a technique used to measure the electrical activity of the brain.
8 to 16 pairs of electrodes are placed on the scalp which record the electrical activity or impulses (in volts) generated by thousands of neurons or nerve cells present in the brain.
It provides the real-time imaging of the electrical activity of the brain.
The recorded impulses are first sent to the amplifier as the magnitude of the brain's electrical impulses is very low.
The amplifier then amplifies the results and show it on the screen in the form of voltage units.
