The production of electricity by ____ involves the striking, bending, or twisting of certain crystals.

• A. Friction
• B. Pressure
• C. Heat
• D. Magnetism

Answer: (B)

The mechanism is the piezoelectric effect: electricity produced when certain crystals are mechanically stressed. When you strike, bend, or twist these crystals, the internal arrangement of charges shifts in a way that creates an electrical voltage across the crystal. If the crystal is part of a circuit, this voltage can drive current. This happens because the crystal lattice lacks symmetry in a way that couples mechanical deformation to electrical polarization. This is different from generating electricity by friction (contact electrification), by heat (temperature differences), or by changing magnetic fields, which rely on other physical processes. The act of applying pressure is the trigger that converts mechanical energy into electrical energy in these piezoelectric materials.