Triboelectric effect from air friction

Steps:

• Identify the process: Aircraft charging occurs via contact and separation of materials, known as triboelectric charging.
• Consider the environment: Flying involves constant interaction between the aircraft surface and surrounding air molecules.
• Evaluate options: Friction generates charge transfer, unlike radiation, heat, or waves which don't directly cause charging.
• Confirm: This matches real-world observations of aircraft static buildup leading to lightning risks.

Why B is correct:

• Friction with air causes electrons to transfer between the aircraft and air particles via the triboelectric effect, where dissimilar materials gain opposite charges upon rubbing.

Why the others are wrong:

• A: Background radiation ionizes air but doesn't systematically charge the aircraft structure.
• C: Heating expands materials but doesn't produce net charge separation.
• D: Radio waves propagate energy but lack the contact needed for charge transfer.

Final answer: B