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Question:

Which device I need to control one way power ONLY when engine is on?

Which device I need to control one way power ONLY when engine is on? I have a need for device that would control direction of power and allow power to go through itself when car is started, and would not allow (prevent battery drainage) when car is off. I do not have access to ignition power just the wire from battery.

Answer:

So you know that there is an emergency?
The roughness of the mirror due to the atoms is small compared to the wavelength of light, so you get simple reflections. In order to see the round shape of those atoms, you need something with a much shorter wavelength than light. For example, electrons (which can have a very short de-broglie wavelength) can see the shape. Editthe size of atoms is measured in angstroms. The wavelength of light is several thousand angstroms. In order to penetrate to see the surface that you are seeing with the electron microscope, you have to have more energy (and shorter wavelength) than the photon has. To the photon, the mirror is a smooth plane.

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