phy mc...(ERGENT!)

Two light bulbs of 220V, 60W and 110V, 100W respectively are

connected in series to a 110V supply. What is the total power

consumed by the light bulbs?

A. 13W

B. 40W

C. 60W

D. 100W

how to caculate?

2 Answers

Rating
  • 1 decade ago
    Favorite Answer

    Resistance of the 220 V bulb, Ra

    = Va^2 / Pa

    = (220)^2 / 60

    = 806.67 ohm

    Resistance of the 110 V bulb, Rb

    = Vb^2 / Pb

    = (110)^2 / 100

    = 121 ohm

    So, total resistance in the circuit, R

    = Ra + Rb

    = 806.67 + 121

    = 927.67 ohm

    Current in the circuit, I

    = V / R

    = 110 / 927.67

    = 0.1186 A

    Therefore, total power consumed

    = I^2R

    = (0.1186)^2(927.67)

    = 13 W

    So, the answer is A. 13 W

    Source(s): Myself~~~
  • 1 decade ago

    the answer is A

    Source(s): calculate
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