Question

The heater element of a toaster is a 5.4 m length of nichrome wire, whose diameter is 0.48 mm. The resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 Ω·m. Assume the toaster is operated at a constant voltage of 120 V.

-When the heater element is at room temperature, is the resistivity in the nichrome wire greater than, less than, or equal to its resistivity when at operating temperature? Explain.

Answer 1

here,

the resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 ohm·m.

the temperature coefficient of nichrome , alpha = 4 * 10^-4 (per degree C)

as the temperature coefficient of nichrome is positive

the resistivity of nichrome increases with increase in temperature

and

toaster is operated at high temperature than room temperature

the resistivity in nichrome wire at room temperature is LESS than when at operating temperature