Three resistors (5, 10, and 15 ohms) are connected in series to a 12 V source.

Question

Three resistors (5, 10, and 15 ohms) are connected in series to a 12 V source. All work must be shown.

What is the equivalent resistance of the circuit?

What is the current through the battery?

What is the current through each resistor?

What is the voltage drop across each resistor?

How much power is dissipated through each resistor?

Answer 1

R = 5 + 10 + 15 = 30 Ohms

i = v/R = 12V/30 Ohms = 0.4 A

i₁ = i₂ = i₃ = i = 0.4 A

v₁ = i₁R₁ = 0.4A·5 ohms = 2 V

v₂ = i₂R₂ = 0.4A·10Ohms = 4V

v₃ = i₃R₃ = 0.4A·15Ohms = 6 V

P₁ = i²R₁ = 0.16A²·5Ohms = 0.8 W

P₂ = i²R₂ = 0.16A²·10Ohms = 1.6 W

P₃ = i²R₃ = 0.16A²·15Ohms = 2.4 W