Problem 1: Alpha. The temperature coefficient of resistivity ? of a certain Ohmic material is defined as the ratio of the fractional change in resistivity Δp/p0 to the absolute change in temperature ΔT. Given the resistivity data below for three conductors X, Y, and Z, which among the choices is the correct order according to increasing ??
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Conductor
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Resistivity (10-8 ?m) at T = 20oC
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Resistivity (10-8 ?m) at T = 50oC
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X
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100
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120
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Y
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50
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100
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Z
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200
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250
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A. X
B. Z
C. Y
D. X
Problem 2: Across the Universe. Which of the following statements is/are Always True?
I. The I-V curve of a nonohmic material is linear.
II. The I-V curve of an ohmic material is increasing.
III. The I-V curve of an ohmic material is logarithmic
a. II only
b. I and III only
c. II and III only
d. I, II and III.