Speed of Light: The speed at which light travels in a vacuum, denoted by "c". It is a fundamental constant that plays a crucial role in many areas of physics.
Planck's Constant: Denoted by "h", it relates the energy carried by a photon to its frequency. Planck's constant is an important constant in quantum mechanics.
Gravitational Constant: Denoted by "G", it determines the strength of gravitational force between two objects. The gravitational constant is essential for understanding gravity on both macroscopic and microscopic scales.