Final answer:
The cracking noise while removing nylon apparel is caused by static electricity, which builds up due to the friction between materials. The noise occurs when the static charge is discharged. This phenomenon is more pronounced on dry days due to poor conductivity of dry air.
Step-by-step explanation:
The cracking noise heard while removing a nylon shirt or stockings is due to static electricity generated during the process (Option 2). When nylon or similar synthetic fabrics move against the body or other surfaces, electrons are transferred due to friction. This transfer of electrons builds up static electricity, which can cause a striking noise or even a spark when the static charge is discharged upon touching a conductive material. Examples of static electricity are familiar in everyday life, such as clothes sticking together after being in a dryer, shocks from doorknobs after walking on a rug, or balloons sticking to walls after being rubbed on hair.
These shocks from static electricity are more common on dry days because dry air does not conduct electricity well, allowing a larger static charge to build up on the surface of materials. To mitigate static electricity risks, precautions such as discharging oneself before pumping gasoline or using conductive materials in hospital operating rooms are common practices.