Power in Circuits Video Lessons

Concept

# Problem: Two light bulbs have resistances of 400 Ω and 800 ΩPart AThe two light bulbs are connected in series across a 120- V line. Find the current through each bulb.Enter your answers numerically separated by a comma.I400, I800 =______APart BFind the power dissipated in each bulb.P400, P800 =________WPart CFind the total power dissipated in both bulbs.P =______W

###### FREE Expert Solution

Part A

Current:

$\overline{){\mathbf{i}}{\mathbf{=}}\frac{\mathbf{V}}{{\mathbf{R}}_{\mathbf{e}\mathbf{q}}}}$

For resistors in series:

$\begin{array}{rcl}{\mathbf{R}}_{\mathbf{e}\mathbf{q}}& \mathbf{=}& {\mathbf{R}}_{\mathbf{1}}\mathbf{+}{\mathbf{R}}_{\mathbf{2}}\\ & \mathbf{=}& \mathbf{400}\mathbf{+}\mathbf{800}\end{array}$

Req = 1200Ω

83% (458 ratings)
###### Problem Details

Two light bulbs have resistances of 400 Ω and 800 Ω

Part A

The two light bulbs are connected in series across a 120- V line. Find the current through each bulb.
I400, I800 =______A

Part B
Find the power dissipated in each bulb.
P400, P800 =________W

Part C
Find the total power dissipated in both bulbs.
P =______W