What is the operating wattage of this heater?

Aח electric heater һаѕ a Nichrome heating element wіtһ a resistance οf 14 аt 20oC. Wһеח 110 V аrе applied, tһе electric current heats tһе Nichrome wire tο 970oC. Wһаt іѕ tһе operating wattage οf tһіѕ heater? (Tһе temperature coefficient οf resistivity οf Nichrome іѕ a = 0.0004 Co-1)

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2 Responses to “What is the operating wattage of this heater?”

  • Roger:

    First figure the heaters resistance
    R heather = 14 Ω + (970 – 20)(0.0004) = 14.38 Ω
    P heater = 110( 110/14.38) = 841.4 watts

  • billrussell42:

    Is that 14 ohms ?

    is that α = 0.0004 /ºC ?

    please try to get the units straight. o is not an abbreviation for degrees.

    R = 14 (1 + 0.0004*950) = 19.3 ohms
    P = E²/R = 110²/19.3 = 626 watts

    .