Lightbulb A is marked \"15.0 W 120 V,\" and lightbulb B is marked \"60.0 W 120 V

Question

Lightbulb A is marked "15.0 W 120 V," and lightbulb B is marked "60.0 W 120 V." These labels mean that each lightbulb has its respective power delivered to it when it is connected to a constant 120-V source.

(a) Find the resistance of each lightbulb

(b) During what time interval do 1.40 C pass into lightbulb A?
xxxx ()

(c)the charge different upon its exit versus its entry into the lightbulb?

Yes or No    

(d) In what time interval do 1.50 J pass into lightbulb A?

(f) Find the cost of running lightbulb A continuously for 30.0 days, assuming the electric company sells its product at $0.110 per kWh.

R(15.0 W 120 V) = xxxxx   ? R(60.0 W 120 V) = xxxxx ? Lightbulb A is marked "15.0 W 120 V," and lightbulb B is marked "60.0 W 120 V." These labels mean that each lightbulb has its respective power delivered to it when it is connected to a constant 120-V sc (a) Find the resistance of each lightbulb. R(15.0 w 120 v) R(60.0 w 120 V) = ) During what time interval do 1.40 C pass into lightbulb A? (c) Is the charge different upon its exit versus its entry into the lightbulb? O Yes ONo Explain This answer has not been graded yet. In what time interval do 1.50 1 pass into lightbulb A? (e) By what mechanisms does this energy enter and exit the lightbulb? Explain This answer has not been graded yet. (f) Find the cost of running lightbulb A continuously for 30.0 days, assuming the electric company sells its product at $0.110 per kWh.

Explanation / Answer

Lightbulb A is marked "15.0 W 120 V,"
Lightbulb B is marked "60.0 W 120 V.

(A)
We know, P = V^2/R

Resistance of -
Lightbulb A
15.0 = 120^2/Ra
Ra = 960


Lightbulb B
60.0 = 120^2/Rb
Rb = 240

(B)
Current flowing in the Lightbulb A, V = I*R
I = V/Ra
I = 120/960
I = 0.125 A

Now,
t = Q/I
t = 1.40 C / 0.125 A
t = 11.2 s
Time, t = 11.2 s

(C)
No; the exiting charge is the same amount as the entering charge.

(D)
LightbulbA uses 15.0 J/s

1 J = 1/15.0 s
1.5 J =  1.5/15 s = 0.1 s

Time taken to pass 1.5 J, t = 0.1 s

(f)
Price =  $0.110 per kWh
Time = 30 * 24 * 3600 s =

Light Bulb A uses Energy = 15 J/s
Total Energy used by Light Bulb A, = 15.0 *  30 * 24 * 3600 = 3.888* 10^7 J

Cost of 3.6 * 10^6 J = $ 0.110
Cost of 3.888* 10^7 J =   $ 0.110 * (3.888* 10^7)/(3.6 * 10^6) = $1.188

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