Solution
Find the unknown emf E- The current measured by the ammeter is I = 1.5 A and this is the current flow in
resistance 12 ohms and we will use Kirchhoff's rules in our solution to get E The figure below shows the directions of currentand the traveling paths of loops-
apply the loop rule to get the variables where the loop rule is a statement that the electrostatic force is conservative
Suppose around a loop, measuring potential differences across circuit elements as we go and the algebraic sum oftheese differences is zero when We return to the starting poin use loop 1 and apply equation 26.6 as showin the figure below where the direction of our travel is counterclockwiseto get the current flows in resistance 48 Q which will help us to get the current shows in 15 ohms
,Visnegativebecausethedirectionoftravelingisfrompositivetonegativeterminalinthebattery(Seefigure26.8a).Theterms(I43ohms)(48ohms)and(1.5A)(12ohms)arepositivebecausethetravelingdirectionisoppositetothedirectionofthe
current Now we can solve the summation for and we will get
Now l use the junction rule where the junction rule is based on conservation of electric charge and the current enter:ajunction point is equal to the current flOWs out from this point, so in our circuit, We could get the current flow in , whereenters point a, as shown in the figure below while