I don't know how to solve this physics homework?

Question

a certain toaster has a heating element made of Nichrome wire. when the toaster is first connected to a 120-V source (and the wire is at a temp of 20C), the initial current is 1.8A. however, the current begins to decrease as the heating element warms up. when the toaster reaches its final operating temp, the current drops to 1.53A.

(a) find the power delivered to the toaster when it is at its operating temp. answer is 184W

(b) what is the final temp of the heating element? answer is 461C

Answer 1

(a)=P=120*1.53 = 183.6 watts

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starting resistance at 20 C:

Ri=120/1.8 = 66.66 ohms

final resistance:

Rf=120/1.53 = 78.43 ohms

The temperature coefficient of resistivity for nichrome wire

is: a=0.0004 C^-1

Rf=Ri(1+a(T-Ti))

solve for T

T=Ti+(Rf/Ri-1)/a

T=20+((78.43/66.66)-1)/(0.0004)

= 461.41 C "answer"

Answer 2

A.  Power = current x voltage = 1.53 x 120 = 184 watts

B.  Don't know.  But it would have to do with the temperature rise per watt and probably the size of the wire.  You may find this information in a wire table.