Final answer:
A person speaking loudly outside the door and preventing the ability to hear the teacher is an example of auditory noise, which is unwanted sound that interferes with the primary signal, in this case, the teacher's voice.
Step-by-step explanation:
The situation described, where a person speaking loudly outside the door interferes with your ability to hear the teacher, is an example of auditory noise. In the context of sound and hearing, noise refers to unwanted sound that is not the primary signal one is trying to listen to. The loudness of background noise, like a person speaking loudly or sounds from a crowded roadway, can drown out other sounds making it hard to focus on the sound you want to hear, which in this case, is the teacher's voice. This form of interference is a common challenge in environments where sound intensity varies, as the energetically vibrating sources produce loud sounds that can be hazardous to hearing over time.