Final answer:
In Bohr's classical model, a hydrogen atom's electron moves in a circular orbit because of the balance between Coulomb and centripetal forces, not a torque creating angular motion from linear motion. Quantum mechanics further explains the behavior with an electron cloud model, eliminating the need for a classical force to initiate circular motion.
Step-by-step explanation:
The question revolves around the formation of a hydrogen atom and the transition from linear motion to circular motion without an apparent torque, which might seem to violate conservation of angular momentum.
In classical physics, as detailed in Bohr's model, an electron in a hydrogen atom moves in a circular orbit around the proton due to the Coulomb force acting as the centripetal force. This circular motion is a result of the balance between the Coulomb force and the centripetal force needed to keep the electron in a stable orbit.
The formation of angular motion from what initially appears as linear attraction between the electron and the proton is attributed to the inherent angular momentum possessed by the electron in quantum mechanics. No classical force is required to "turn" the linear motion into circular motion, as quantum mechanics describes the behavior of the electron in terms of probability distributions rather than deterministic paths.
Moreover, in quantum mechanics, the concept of an electron following a specific path within an atom is replaced by the electron cloud model, where the electron's position is described by a probability density rather than a precise trajectory. This framework circumvents the need for an initiating torque to establish circular motion.