Questions tagged [energy]
Energy is defined as the amount of work that can be performed by a force, measured in joules (J). Energy is power integrated over time; power (W) is energy per second (J/s). This is a poor tag to use. Please consider if your question relates to energy as defined in physics; don't use it as a synonym for power or capacity.
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Lightning bolt vs. batteries: a coulomb in everyday terms
I am trying to decide if the information on the wikipedia page
http://en.wikipedia.org/wiki/Coulomb#In_everyday_terms
is reasonable. In particular the statements that a lightning bolt has about 15 ...
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Does turning a lighbulb on and off repeatedly use more energy than just leaving it on for hours?
Let's say I have a 60W bulb in a lamp in my bedroom. If I kept the lamp on for 2 hours straight but the next day, I switched it on and off 10 times in intervals of 5 minutes. Which scenario would use ...
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Why is an inductor not a good antenna?
[An antenna must have] current flowing along its length, so that the resulting fields radiate that energy into space. (Receiving antennas are just this process in reverse).
[This] explains why ...
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How to compare mAh and Wh
When looking at consumer electronic devices with batteries I sometimes see the battery capacity listed in Wh (watt hours) and sometimes in mAh (milliamp hours). I would like to be able to compare the ...
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What is the speed of "electricity"?
In a distribution grid, what is the speed of
energy
signal
Is it strictly the same?
And how is synchronisation achieved? Is an electric grid essentially an orchestra where everyone is the chief ...
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Why are deep cycle batteries rated in amp hours instead of watts hours?
Why are deep cycle batteries rated in amp-hours instead of watt-hours? For example if I see a 85Ah battery, I multiply 85Ah x 12V to get 1020 watts. As household electricity use is measured in watt ...
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What's the highest theoretical energy density for a chemical battery?
This is more a physics/chemistry/nanotech question, but what's the theoretical best energy density you could get out of a chemical battery (or fuel cell), if you could arrange atoms in any manner you ...
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Is a microwave's output power proportional to the mass of its contents?
My friend and I are having a heated debate.
On the one hand, he thinks that a microwave oven that is empty, consumes almost no power (not considering lights, lcd, etc). He says that once you put an ...
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I need the most basic circuit diagram for wireless energy transfer please
I have been all over the net looking for the most basic circuit diagram or instructions to put together a small project on wireless energy transfer. If anyone knows of a good schematic that is super ...
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Why is it so problematic to have close to zero standby power consumption?
Each electronic device consumes electric power when it is "idle" unless it has a mechanical switch. I can understand that for example a TV with a remote control needs to "be ready" to receive a ...
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Why is home voltage value higher during the night?
I have been monitoring the voltage in my own home (Mexico 120V 60Hz). I have been graphing the values every minute and I'm starting to notice that during the morning voltage gets up to 127, and during ...
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Does this device which claims to reduce reactive energy from a house work?
I've opened a device that states that it can reduce the reactive energy from a house, by plugin it directly to the power outlet/wall socket. I think it is a con, so I've opened it and I saw this black ...
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In theory, is it possible to make a logic gate that uses zero current?
CMOS greatly reduces the current draw of ICs because one of the complementary FETs is always in the non-conducting mode, so there is only a flow of current during the transition between states, which ...
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Will repeatedly turning a light bulb on and off damage it?
I have been hearing a common saying that if one keeps switching the lights on and off you will probably damage the light bulb itself, since every time you close the switch there would be a sudden rush ...
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Why do capacitors have less energy density than batteries?
The basic operating principle of a battery is, in order to charge it, the electrons are removed from cathode and moved to anode by applying voltage. And to discharge, the electrons move from cathode ...
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