Electric Power: V^2/ohm Has SI Units of Power

[predentalgirl1]

Show the quantity volts squared per ohm (V^2/ohm) has SI units of power.








P = V x I
where
P is the power (watt or W)
V is the potential difference (volt or V)
I is the current (ampere or A)
From Ohm’s law
I = V / R
where
R is the resistance (Ohm or Ω).
So substituting in the above equation
P = V x (V/R)
P = V2 /R
So in unit , watt = (volt)2 / Ω


OR
I can rewrite, V^2/R = V.V/R = V.I
From definition of potential difference as Work done per unit charge, V = W/q
Unit volt, V = unit of W/unitof chaarge = J/C
Also current = charge/time
I = C/s
so, V^2/R = V.V/R = V.I
= J/C xC/s = J/s
= watt, (unit of power.)


Which seems most reasonable?

 

[rock.freak667]

You should use the 2nd one as that uses what they gave you V^2/omega to get J/s.