A Nichrome wire is used as a heating element in a toaster.From the moment the toaster is first turned on to the moment the wire reaches it maximum temperature,the current in the wire drops by 20.0% from its initial value.What is the temperature change in the wire? The temperature coefficient of resistivity for Nichrome is 0.000400 (°C)^-1. A) 200°C B) 400°C C) 500°C D) 625°C E) 300°C

Question

Quizplus · Accepted Answer

We can use the formula for the temperature coefficient of resistivity to solve for the temperature change:

ΔR/R = αΔT

where ΔR/R is the fractional change in resistance, α is the temperature coefficient of resistivity, and ΔT is the temperature change in Celsius.

Since the current drops by 20%, the resistance of the wire increases by 25% (since R = V/I, and V is constant). Therefore, ΔR/R = 0.25.

Substituting in the given value for α, we get:

0.25 = 0.000400 ΔT

ΔT = 625°C

Therefore, the temperature change in the wire is 625°C, so the answer is choice D.

A Nichrome Wire Is Used as a Heating Element in a Toaster.From