The heating element of an electric stove consists of a heater wire embedded with

Question

The heating element of an electric stove consists of a heater wire embedded within an electrically insulating material, which in turn is inside a metal casing. The heater wire has a resistance of 27 at room temperature 25.0 C and a temperature coefficient of resistivity = 2.6×103 (C)1 . The heating element operates from a voltage of 120 V .

Part A

When the heating element is first turned on, what current does it draw?

Express your answer using two significant figures.

Part B

What electrical power does it dissipate?

Express your answer using two significant figures.

Part C

When the heating element has reached an operating temperature of 300 C, what current does it draw?

Express your answer using two significant figures.

Part D

What electrical power does it dissipate in this case?

Express your answer using two significant figures.

Explanation / Answer

Part A) I1 = V/R1 = 120/27 = 4.4 A

Part B) P1 = V2/R1 = 1202/27 = 530 W

Part C) R2 = R1(1 + T) = 27[1 + (2.6 * 10-3 * (300 - 25))] = 46.3

So, I2 = V/R2 = 120/46.3 = 2.6 A

Part D) P2 = V2/R2 = 1202/46.3 = 310 W

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