The working of the quartz crystal in the watch is based on the A. Piezo – electric Effect B. Edison Effect C. Photoelectric Effect D. Johnson Effect

The correct answer is A. Piezo – electric Effect.

The piezoelectric effect is the ability of certain materials to generate an electric charge when they are subjected to mechanical stress. This effect is reversible, meaning that applying an electric field to a piezoelectric material will cause it to deform.

Quartz is a piezoelectric material,

and it is this property that is used in quartz watches. The quartz crystal in a watch is cut into a specific shape and then subjected to a voltage. This causes the crystal to vibrate at a very precise frequency. The frequency of the vibration is then used to keep time.

The other options are incorrect. The Edison effect is the emission of electrons from a metal surface when it is heated. The photoelectric effect is the emission of electrons from a metal surface when it is exposed to light. The Johnson effect is the generation of noise in an electronic circuit due to the random motion of electrons.