A laboratory manual claims that the metal used for a uniform cylindrical wire can be…
PHYSICS · Multi-part · CBSE · Physics · Current Electricity · Current Electricity
Problem
A laboratory manual claims that the metal used for a uniform cylindrical wire can be identified solely from three measured quantities: the wire’s length, its diameter, and its electrical resistance at room temperature. Assume the wire is otherwise unmarked and uncontaminated.
(a) Describe the specific intrinsic property of the metal that the laboratory manual is relying on for identification, and explain how simultaneous knowledge of length, diameter, and resistance allows that property to be determined.
(b) Discuss two distinct experimental or environmental factors that could cause a student to misidentify the metal even if the three measurements are performed carefully.
(c) A student measures the resistance of a wire that is in fact aluminum but—using a standard room-temperature data table—concludes that it is nichrome. Provide a plausible physical explanation for this error and describe one additional measurement that could help the student avoid misidentification.