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Chapter 4: Q37E (page 843)

In Europe the standard voltage in homes is 220 V instead of the 120 used in the United States. Therefore a “100-W” European bulb would be intended for use with a 220-V potential difference (see Problem 25.36). (a) If you bring a “100-W” European bulb home to the United States, what should be its U.S. power rating? (b) How much current will the 100-W European bulb draw in normal use in the United States?

Short Answer

Expert verified
  1. The U.S power rating for a 100-W European bulb is 29.8 W.
  2. The current drawn by a 100-W European bulb is 0.248 A.

Step by step solution

01

(a) Determination of the U.S power rating for 100-W European bulb.

The expression of power is,

P=V2R

The ratio of power dissipation for the U.S to the European is,

PUSPE=VUS2/RVE2/R=VUSVE2=120V220V2PUS=(100W)120V220V2=29.8W

Thus, the U.S power rating for the 100-W European bulb is 29.8 W.

02

(b) Determination of the current drawn by 100-W European bulb.

Expression of power in terms of voltage and current is,

P = Vl

Solve for current I,

l=PV=29.8W120V=0.248A.

Thus, the current drawn by 100-W European bulb is

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