When the Captain's NORM/EMER switch on the Audio Control Panel is selected to EMRG, what happens?

When the Captain's NORM/EMER switch on the Audio Control Panel is selected to EMRG, the Captain's headset is automatically configured to receive audio from NAV 1 and VHF 1. This selection ensures that the flight crew has immediate access to critical communication channels essential for emergency situations, namely navigation and voice communications.

The design of this system prioritizes essential information in emergencies, as it helps the Captain to maintain situational awareness and communicate effectively with air traffic control or other relevant parties while potentially disregarding non-essential audio inputs that could otherwise distract from handling the emergency.

In the context of the other options, muting the Captain's headset or turning off all audio channels would hinder communication rather than facilitate it during emergency procedures. Additionally, the activation of emergency lights is not directly related to the function of the Audio Control Panel's EMRG setting, as that control is specifically focused on audio management.