PYQ NEET- Electric Current And Current Density

1. 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.

2. 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.

3. 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.