Static electricity in photocopying Steps:

• Identify devices using static charges: static electricity involves non-moving charges that attract or repel.
• Recall photocopier process: xerography uses electrostatic charges to transfer toner.
• Eliminate magnetic/electromagnetic devices: hard drives, motors, and transformers rely on moving charges or fields.
• Confirm via definition: static charges are key in electrostatic attraction for imaging.

Why B is correct:

• Photocopiers use static electrical charges in xerography, where a photoconductive drum is charged electrostatically to attract oppositely charged toner particles per Coulomb's law.

Why the others are wrong:

• A: Computer hard drives use magnetic fields for data storage, not static charges.
• C: Motors convert electrical energy to mechanical via electromagnetic induction, involving current flow.
• D: Transformers step up/down voltage using electromagnetic induction in coils, without static charges.

Final answer: B