Apa yang dilakukan kilogram dalam definisi satuan volt?


Jawaban:


32

Itu bagian dari the Force. Yah, sebenarnya paksa saja. Yang merupakan percepatan kali massa.

V=JC

J=Nm

N=kgms2

C=As


5
"Gunakan Kekuatan, Kamil!"
Kroltan

29

Tegangan digunakan untuk mengukur perbedaan potensial antara satu titik dan titik referensi. Titik referensi ketika tegangan arde menjadi simpul atau tegangan titik. Sekarang potensial didefinisikan sebagai "Pekerjaan yang dilakukan dalam membawa muatan titik dari tak terbatas ke lokasi yang diberikan". Pekerjaan yang dilakukan adalah Gaya yang dikalikan dengan perpindahan dan Gaya melibatkan massa partikel (muatan unit + ve), yang dalam satuan SI adalah dalam kg.


2
Ini menjelaskan mengapa , sedangkan jawaban yang diterima hanya sekelompok formula yang hanya benar-benar masuk akal jika Anda sudah mengerti mengapa.
David Richerby

12

Biarkan menjadi daya dalam watt, saya arus di amp, W bekerja di Joules,PIW

Percepatan dalam meter per detik 2 D jarak dalam meter, M Mass kg.Asecond2 DM

Waktu dalam detik, F Memaksa dalam newton dantegangan V dalam volt.TFV

Kita tahu sangat V = PP=VI .V=PI

P=WT.

W=FD

F=MA.

Putting all this together we see.

V=PI=WIT=FDIT=MADIT=MDDITT2=MD2IT3

Using standard SI units the volt is therefore kgm2As3


8

Imagine a uniform electric field, pointing to the right. Consider two points A,B, where B is one meter to the right of A. Suppose the difference in potential between A and B is one volt.

At point A, put an object with a mass of one kilogram which has a positive charge of one coulomb (one amp-second). The object will be pushed towards B by the electric field. As it moves towards B, it will experience a force sufficient to accelerate it at a rate of one meter per second per second.

In other words, one volt is the potential difference which, over a distance of one meter, will cause an object with charge one coulomb and mass one kilogram to accelerate at a rate of one meter per second per second.

If the object's mass were two kilograms, it would only accelerate at one-half meter per second per second.


5

As other have mentioned, voltage is a measure of energy per unit charge. But in the physics of E&M fields, voltage is also used to calculate the electric field. Specifically:

E=V

In English, this means that the gradient of the voltage gives the electric field. (If you don't know vector calculus, think of it as the vector equivalent of E = dV/dx.) The units of the electric field are Newtons/Coulomb (force / charge), and mass is part of the definition of force. That's why the kilogram is there -- the energy in an electric circuit is transferred through a force field! You can see this more clearly if you separate out the units:

Physics:Voltage=Efielddistance 
Units:V=NCm
V=N1Cm
V=kgms21Asm
V=kgm2As3

4

As an interesting side light. It may soon be that the kilogram is defined in terms of the volt. (Well more than just the volt.) See the watt balance.


2
"Any laboratory which had invested the (very considerable) time and money in a working watt balance would be able to measure masses to the same accuracy as they currently measure the Planck constant." Infinite awesomeness achieved.
Ignacio Vazquez-Abrams

@IgnacioVazquez-Abrams, I read a nice physics today article about it few months ago, still here.nymanz.org/Nonlinear/documents/…
George Herold

although I find this an interesting find and a valuable comment, it doesn't even try to answer the question asked... George, please try to answer what kg is doing in V definition, otherwise this answer would be eligible to be flagged as "not an answer".
vaxquis

@vaxquis, flag away :^) I thought everyone else answered the question. I guess if you read between the lines, the implication is that there are a limited number of fundamental constants. And a force can be mass * acceleration (little g) or B x I * L (a current in a B field for some length.)
George Herold

little g is actually the earth's gravitational constant, not acceleration. Acceleration is a.
vaxquis
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