- The answer is (A) R/n
Let’s think step-by-step.
When a wire is cut into n equal parts, the length of each part becomes l/n. Since the resistivity of a wire is directly proportional to its length, the resistivity of each part will be ρ/n. The equivalent resistance of the parallel combination of n resistors is R/n.
- The answer is (A) Ohm’s law
Let’s think step-by-step.
The electric current flowing through a conductor is directly proportional to the potential difference applied across it, and inversely proportional to its resistance. This is known as Ohm’s law.
- The answer is (C) 2ρ
Let’s think step-by-step.
The resistivity of a wire is given by ρ = ρl/A, where ρ is the resistivity, l is the length, and A is the cross-sectional area. When a wire is stretched to double its length, its cross-sectional area will become half. So, the resistivity of the wire will become ρ/2.
