power through a resistor question

guru200773

Joined Apr 26, 2010
101
you are wrong Mr.sage.radachowsky.. U have to find out the voltage drop on each resistor in order to use that V^2/R formula not the source voltage..Whatever the formula u want use u need the current.. so I=V/R(eq). R(eq)=R(1)+R(2)+R(3)+R(4)=5+7+10+20=42
therefore.. I=10/42=0.238A.. Use P=I^2*R formula i.e
power on R(1) = 0.2822, power on R(2)=0.3965, power on R(3)=0.5664 power on R(4) =1.1328 Add the all power in each resistor then total power is P(t)=2.3779--------------------- eq(1)

another of finding total power is P(t)= V(source)*I=10*0.238=2.38-------------------- eq(2)
both eq(1) and eq (2) are equal [eq(1)sightly varies because of rounding off of decimal points in calculations....:):):)]


If u know the total power and source Voltage.. find current by using I=P(t)/V
then use formula I^2/R to find the power drop on resistor.....
 
Last edited:

guru200773

Joined Apr 26, 2010
101
oh i am extremely sorry dude.. i didnt notice that and Me only wrong.... ITS PARALLEL circuit so what Mr.Sage.radachowsky is absolutely correct sorry dude pls pardon me....:( :(
 
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