Question

you have three resistors connected in series: r1 = 10 ω, r2 = 25 ω, and r3 = 15 ω. what is the total equivalent resistance req? req = r1 + r2 + r3 +...
options: 20 ω, 50 ω, 60 ω, 10 ω
two resistors are connected in parallel: r1 = 12 ω and r2 = 6 ω. calculate the total equivalent resistance req. req = (1/r1 + 1/r2 + 1/r3)^-1
options: 4 ω, 10 ω, 6 ω, 18 ω

Explanation:

Step1: Sum series resistances

$R_{eq} = 10\ \Omega + 25\ \Omega + 15\ \Omega$

Step2: Calculate series equivalent

$R_{eq} = 50\ \Omega$

Step3: Compute parallel resistance sum

$\frac{1}{R_{eq}} = \frac{1}{12\ \Omega} + \frac{1}{6\ \Omega} = \frac{1 + 2}{12\ \Omega} = \frac{3}{12\ \Omega}$

Step4: Find parallel equivalent

$R_{eq} = \frac{12}{3}\ \Omega = 4\ \Omega$

Answer:

1. 50 Ω
2. 4 Ω