What characteristic of liquid crystals allows them to block light when a voltage is applied?

Liquid crystals have unique properties that enable them to modulate light in response to an electric field. The characteristic that allows them to block light when a voltage is applied primarily relates to their ability to change direction.

When no voltage is applied, the molecules in a liquid crystal display a certain alignment that allows light to pass through. However, when a voltage is introduced, these molecules respond by reorienting themselves. This change in orientation disrupts the pathway of light, effectively blocking it. The alignment of liquid crystal molecules can switch between various states depending on the electrical stimulus, and this property is fundamental to the operation of devices such as liquid crystal displays (LCDs).

Understanding the importance of molecular orientation and how it affects light transmission is essential for grasping how liquid crystal technology functions in electronic displays.