A light bulb is rated at 60 W when plugged into a standard 120 V outlet. (Assume

Question

A light bulb is rated at 60 W when plugged into a standard 120 V outlet. (Assume electrical energy costs $0.18/kW•h.)

(a) Determine the resistance of the bulb.

(b) Determine the current in the bulb.

(c) Determine the cost of running the bulb continuously for 31 days.

(d) Determine the power drawn by the bulb if connected to a 12 V car battery.

These are my teachers requirements if you could please follow them I would really appreciate it thank you :)

In addition to being neat and clear, and actually answering the question, you must:

1) show the original principle (often in equation form)

2) substitute variables as needed

3) solve it first (before substituting numbers)

4) show every substitution (with units and correct sig figs)

5) present a boxed answer (with units and correct sig figs)

In a Force problem in more than one dimension, you MUST start with a Free Body Diagram.

Explanation / Answer

I can answer only 1 question at a time

a)
P = 60 W
V = 120 V
R= V^2/P
= 120^2/60
= 240 ohm

b)
I = V/R
= 120/240
= 0.5 A

c)
31 days = 31*24 hr
E = 60 W* 31*24 hr
= 44640 W-hr
= 44.64 KW-hr
cost = 44.64 * $0.18
=$8.04

d)
P = V^2/R
= 12^2/240
=0.6 w

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