Concepts Of Physics MCQ Edition [Volume 2]PhysicsElectric Current in Conductors
Consider the circuit displayed in figure (a). Determine the current in the circuit, the potential drop across the 5 resistor, and the potential drop across the 10 resistor. Additionally, evaluate whether these three quantities are the same for the circuit in figure (b).
Options
- A1.2 A , 6 V , and 12 V respectively; the values remain the same for figure (b)
- B0.4 A , 2 V , and 4 V respectively; the values are different for figure (b)
- C1.2 A , 6 V , and 12 V respectively; the values are different for figure (b)
- D0.4 A , 2 V , and 4 V respectively; the values remain the same for figure (b)
Correct answer
C. 1.2 A , 6 V , and 12 V respectively; the values are different for figure (b)
Step-by-step solution
In both circuits, the total resistance is the sum of the series resistors: R_ eq = 10 + 5 = 15 For the circuit in figure (a), the two batteries are connected such that their polarities aid each other (both have their positive terminals on the left). The net electromotive force (EMF) is: E_ net, a = 12 V + 6 V = 18 V The current in circuit (a) is: I_ a = E_ net, a R_ eq = 18 15 = 1.2 A The potential drop across the 5 resistor is: V_ 5 = I_ a 5 = 1.2 5 = 6 V The potential drop across the 10 resistor is: V_ 10 = I_ a