NEED Help From Basic Ohm's Law to E=SqRt of P*R

Feb 12, 2008 2 Replies

Basic Ohm's Law E P ----------------



---------------- I R E I



What simple Ohm's Law formulas get combined to (Exp.E=RxI E=P/I} to arrive at I=SqRt of P/R V=SqRt of P*R P= V^2/R



Thank You for any advice Frustrated Apprentice


"rdelec"

** P = VI

Substituting V/R for I, gives P = Vsquared / R

-------------------------

V = P / I

Substituting V/R for I, gives V = P * R /V

So V squared = P*R

------------------------

I = P / V

Substituting I*R for V, gives I = P /I*R

So, Isquared = P/R

..... Phil

I can't read your formulas so well, so I will repeat them.

E=I*R P=E*I

If substitute the first expression that equals E for the E in the second formula, you get P=(I*R)*I=I*I*R=(I^2)*R.

If you take the square root of both sides of P=(I^2)*R you get sqrt(P)=I*sqrt(R). Then dividing both sides by the sqrt(R) you get sqrt(P)/sqrt(R)=sqrt(P/R)=I.

If you rearrange the first to solve for I by dividing both sides by R, you get E/R=I. Then you can substitute this equivalent of I for the I in the power formula. P=E*(E/R)=E*E/R=(E^2)/R.

If you take the square root of both sides of P=(E^2)/R, you get sqrt(P)=E/sqrt(R). Multiplying both sides by sqrt(R) you get sqrt(P)*sqrt(R)=sqrt(P*R)=E.

Is that what you needed?

Regards, John Popelish

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required