Green energy nudges come with a hidden cost

All across the United States, many households receive energy bills comparing their use to that of similar neighbors to remind them to use less energy. At most companies, employees are automatically enrolled in 401(k) plans ...

50 US coal power plants shut under Trump

Fifty coal-fired power plants have shut in the United States since President Donald Trump came to office two years ago, an environmental organization said Thursday.

Banning offshore oil and gas drilling

Last week, New York's Governor Andrew Cuomo signed a bill passed in February that banned oil and gas drilling off New York's coastline. The state's action was in part a response to the Trump Administration's plan to encourage ...

Demonstrating a weak topological insulator in bismuth iodide

Topological insulators are one of the most exciting discoveries of the 21st century. They can be simply described as materials that conduct electricity on their surface or edge, but are insulating in their interior bulk. ...

Tapping into 100-year supply of natural gas

It is a figure that has been thrown around quite a bit lately in the energy debate – the United States has enough energy in shale to provide all of the nation's transportation fuels for 100 years. But two challenges remain ...

Turn off a light, save a life, says new study

We all know that turning off lights and buying energy-efficient appliances affects our financial bottom line. Now, according to a new study by University of Wisconsin-Madison researchers, we know that saving energy also saves ...

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Energy level

A quantum mechanical system or particle that is bound, confined spatially, can only take on certain discrete values of energy, as opposed to classical particles, which can have any energy. These values are called energy levels. The term is most commonly used for the energy levels of electrons in atoms or molecules, which are bound by the electric field of the nucleus. The energy spectrum of a system with energy levels is said to be quantized.

If the potential energy is set to zero at infinity, the usual convention, then bound electron states have negative potential energy.

Energy levels are said to be degenerate, if the same energy level is obtained by more than one quantum mechanical state. They are then called degenerate energy levels.

This text uses material from Wikipedia, licensed under CC BY-SA