What is the magnitude of the potential difference between points C and D for the circuit shown in the figure? The battery is ideal,and all the numbers are accurate to two significant figures.
A)6.0 V
B)4.0 V
C)3.0 V
D)2.0 V

Question

What is the magnitude of the potential difference between points C and D for the circuit shown in the figure? The battery is ideal,and all the numbers are accurate to two significant figures. 
A)6.0 V 
B)4.0 V 
C)3.0 V 
D)2.0 V

Quizplus · Accepted Answer

The potential difference between points C and D can be found by summing the potential differences across each element in the path from C to D. The potential difference across the 3 Ω resistor and the 6 Ω resistor can be found using Ohm's law:

V = IR

For the 3 Ω resistor, I = (12 V)/(3 Ω) = 4 A, so V = (4 A)(3 Ω) = 12 V 
For the 6 Ω resistor, I = (12 V)/(6 Ω) = 2 A, so V = (2 A)(6 Ω) = 12 V

Therefore, the potential difference from C to D is 12 V - 8 V = 4 V.

The potential difference across the 2 Ω resistor and the 1 Ω resistor do not contribute to the potential difference from C to D since both points are at the same potential due to the wire connecting them.

What Is the Magnitude of the Potential Difference Between Points