A certain toaster has a heating element made of Nichrome resistance wire. When t

Question

A certain toaster has a heating element made of Nichrome resistance wire. When the toaster is first connected to a 140-V source of potential difference (and the wire is at a temperature of 20.0 degree C), the initial current is 1.70 A, but the current begins to decrease as the resistive element warms up. When the toaster reaches its final operating temperature, the current has dropped to 1.53 A. Find the power the toaster converts when it is at its operating temperature. What is the final temperature of the heating element?

Explanation / Answer

(a)
Power = Potential Difference * Current
Power = 140 * 1.53 Watt
Power = 214.2 Watt

(b)
Temperature coefficient of resistivity for nichrome = 0.4x10^-3

Intial Resistance at Temperature T = 20o c
Resistance Rin = 140/1.70 = 82.35 ohms

At operating temperature (T):
Resistance Rfi = 140/1.53 = 91.5 ohms

Rf=Ri(1+ (T-Ti))
solve for T
T=Ti+(Rf/Ri-1)/
T=20+((91.5/82.35)-1)/(0.0004)
T= 297.77 C

Final Temperature of Heating Element, T = 297.77o C

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.