Knowra Joule-second Joule-second The joule-second is the SI unit of action and angular momentum, equal to one joule multiplied by one second. It is dimensionally equivalent to kilogram metre squared per second.
Second : The SI base unit of time, defined by a specified caesium-133 transition frequency. It supplies the time factor in the joule-second.
Reduced Planck constant : Planck's constant divided by two pi, commonly denoted ħ. It is a widely used quantum scale expressed in joule-seconds.
Joule : The SI unit of energy, equal to one kilogram metre squared per second squared. A joule measures energy, whereas a joule-second measures action or angular momentum.
Principle of least action : A formulation of mechanics in which physical trajectories make the action stationary under small variations. Its central quantity has joule-second units.
Action (physics) : A physical quantity with dimensions of energy multiplied by time, central to classical and quantum mechanics. The joule-second is the SI unit used to measure action.
Quantum mechanics : The physical theory describing matter and radiation through quantized states and probabilistic predictions. Joule-seconds set the scale of quantum action in this theory.
Newton metre : A unit equal to one newton multiplied by one metre, commonly used for torque and energy. It shares the dimensions of a joule, not a joule-second.
Canonical quantization : A procedure for constructing a quantum theory by replacing classical variables with operators and imposing commutation relations. The reduced Planck constant, measured in joule-seconds, sets its commutator scale.
Angular momentum : A conserved vector quantity measuring rotational motion, with dimensions of mass times length squared per time. Angular momentum has the same SI unit and dimensions as action.
Bohr model : An early atomic model in which electron angular momentum is restricted to integer multiples of the reduced Planck constant. Its quantization rule assigns angular momentum values in joule-seconds.
Show all 21