Electrostatic attraction from friction-induced charge transfer

Steps:

• Friction from shaking transfers electrons between beads and box.
• Box loses electrons, becoming positively charged.
• Beads gain electrons, becoming negatively charged.
• Opposite charges cause beads to stick to the box's inside surface.

Why B is correct:

• Triboelectric effect: friction causes electron transfer, creating opposite charges that attract per Coulomb's law.

Why the others are wrong:

• A: Neutral beads show no charge transfer from rubbing; box alone can't attract them strongly.
• C: Neutral box provides no opposing charge for attraction to positive beads.
• D: Positive beads and negative box would attract, but contradicts typical plastic-on-plastic charging where box loses electrons.

Final answer: B