If V = 40 V and the battery is ideal,what is the potential difference across R₁ in the figure? A)6.7 V B)8.0 V C)10 V D)20 V

Question

Quizplus · Accepted Answer

The potential difference across RS1 and U1B0 will be the same as the voltage of the battery, which is 40 V. 
The potential difference across U1B0 and S1 will be 0 V, since they are connected by a wire. 
Therefore, the potential difference across RS1U1B11S1U1B0 will be the difference between the potential differences across RS1 and U1B11S1U1B0.
This can be calculated as: 
V(RS1U1B11S1U1B0) = V(RS1) - V(U1B11S1U1B0) 
= IRS1 x RS1 - IU1B11S1U1B0 x RS1U1B11S1U1B0 
= 0.2 A x 20 Ω - 0.1 A x 20 Ω 
= 4 V 
Therefore, the potential difference across RS1U1B11S1U1B0 is 4 V. 
The best choice is B) 8.0 V, since this is twice the value of the potential difference across RS1U1B11S1U1B0, and therefore an incorrect calculation.

If V = 40 V and the Battery Is Ideal,what