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Q & A: Dimensional analysis of electricity

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Most recent answer: 04/15/2015
Q:
sir, my question if from electricity we know,I=Q/T OR,Q=IT -(1) NOW, V=W/Q OR, V=W/IT (FROM(1)) OR, V∝1/I BUT, V∝ I HOW IT IS POSSIBLE?
- brij mohan yadav (age 14)
nagpur,maharashtra,india
A:

What you are doing is called a dimensional analysis, that is you try to determine the physical character of certain quantities (units). Your problem is in the proportionality factors, more specifically: [W] = [I2 R T]

[V] = [I R] = [I (W/I2T)] = [ W / T I]. So, everything is OK dimensionwise. Will voltage in a resistance circuit decrease with I? No, because W is proportional to I2, so V α I.

Tunc

 


(published on 04/15/2015)

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