Question:

From Example 26.2 and sweeps through class lecture on resistance due to AT. A Nichrome wire with radius r has initial resistance R0 = 2.4 Q , when the temperature reaches 28C, and a 9.0 V is being applied to the wire; a) what is its diameter, b) the current I when Temperature is 28C, 0) calculate the length of the wire, d) since you now have all the values you need, use example 26.3 to verify R using the integral method. (Note* work must be clean and orderly to be graded. (25 pts) Material Resistivity Temperature (2 . m) Coefficient * a [ ( c ) - 1 ] Silver 1.59 x 10-8 3.8 x 10-3 Copper 1.7 x 10-8 3.9 x 10-3 Gold 2.44 x 10-8 3.4 x 10-3 Aluminum 2.82 x 10-8 3.9 x 10-3 Tungsten 5.6 x 10-8 4.5 x 10-3 Iron 10 x 10-8 5.0 x 10-3 Platinum 11 x 10-8 3.92 x 10-3 Lead 22 X 10-8 3.9 x 10-3The radius of 22-gauge Nichrome wire is 0.32 mm. Example 26.2 (A) Calculate the resistance per unit length of this wire. Solution Conceptualize Table 26.2 shows that Nichrome has a resistivity two orders of magnitude larger than the best conductors in the table. Therefore, we expect it to have some special practical applications that the best conductors may not have. categorize We model the wire as a cylinder so that a simple geometric analysis can be applied to nd the resistance. Analyze Use Equation 26.10 and the resistivity of Nichrome from E , 3 i L 7 1.0 x 10'6 (2 - m , 3_1 n/m Table 26.2 to nd the resistance per unit length: 1? _ A _ m2 _ (0.32 >