After a long period of use,contacts in an electric bulb socket could corrode and introduce extra resistance in the circuit.Suppose a light bulb socket is very badly corroded and has 10 ohm of resistance.If you are using a 100-W bulb in the corroded socket at 120 V,the actual power dissipated in the bulb is
A)139.5 W.
B)112 W.
C)93.5 W.
D)87.4 W.
E)67.1 W.

Question

Quizplus · Accepted Answer

Using Ohm's Law, we can find the current in the circuit as:
I = V/R = 120/10 = 12 A
The actual power dissipated in the bulb can then be found using:
P = V*I = 120*12 = 1440 W
However, this is the total power dissipated in the circuit, including the resistance in the corroded socket. To find the actual power dissipated in the bulb, we need to subtract the power dissipated in the socket:
P_bulb = P - I^2*R = 1440 - 12^2*10 = 1440 - 1440 = 0 W
This tells us that no power is actually being dissipated in the bulb due to the high resistance of the corroded socket. Therefore, the answer is not listed among the choices.

After a Long Period of Use,contacts in an Electric Bulb