A nichrome wire is tested for its – characteristics at two different temperatures
PHYSICS · Subjective · CBSE · Physics · Current Electricity · Current Electricity
Problem
A nichrome wire is tested for its I–V characteristics at two different temperatures. The observations are:
Temperature 25∘C:
I (A): 0.20, 0.40, 0.60, 0.80
V (V): 1.00, 2.01, 3.02, 4.03
Temperature 120∘C:
I (A): 0.20, 0.40, 0.60, 0.80
V (V): 1.16, 2.36, 3.61, 4.85
(a) For each temperature, calculate the resistance corresponding to every reading and find the mean resistance.
(b) Compare the mean resistances at the two temperatures and compute the percentage increase.
(c) Sketch the V–I graph for each temperature on the same set of axes.
(d) Based on the graphs, state clearly whether the wire obeys Ohm’s law at 25∘C and at 120∘C. Give reasons for any deviation observed at the higher temperature.