Determine the resistance R when I = 1.5 A.
A) 40 Ω
B) 8.0 Ω
C) 85 Ω
D) 28 Ω
E) 32 Ω

Question

Determine the resistance R when I = 1.5 A. 
A) 40 Ω 
B) 8.0 Ω 
C) 85 Ω 
D) 28 Ω 
E) 32 Ω

Quizplus · Accepted Answer

Using Ohm's law, we have: 
V = IR 
V = (10 V) - (5 Ω)(1.5 A) - (2 Ω)(1.5 A) 
V = 2.5 V 
Now, we can use the equation: 
R = V/I 
R = 2.5 V/1.5 A 
R ≈ 1.67 Ω 
However, this is not the total resistance we are looking for. We need to find the equivalent resistance of the circuit. We can start by finding the resistance of the parallel combination of 2 Ω and 5 Ω. Using the equation: 
1/R(parallel) = 1/2 Ω + 1/5 Ω 
R(parallel) ≈ 1.67 Ω 
Now, we can find the equivalent resistance of the circuit by adding the resistance of the remaining 10 Ω in series: 
R(equivalent) = R(parallel) + 10 Ω 
R(equivalent) ≈ 11.67 Ω 
Finally, we can use Ohm's law again to find the resistance R when I = 1.5 A: 
R = V/I 
R = 10 V/1.5 A - R(equivalent) 
R ≈ 8.0 Ω

Determine the Resistance R When I = 1