If a conductor of length l and cross-sectional area A has resistivity …

Question

If a conductor of length l and cross-sectional area A has resistivity ρ, halving the length AND halving the area gives new resistance

Accepted Answer

A. {'text': 'R', 'label': 'A'}

1. Original resistance R = ρ l / A.
2. Half length: l → l/2. Half area: A → A/2.
3. New R' = ρ (l/2) / (A/2) = ρ l / A = R.
4. So halving both length and area leaves the resistance unchanged.
_Source: NCERT Class 12 Physics, Ch 3 "Current Electricity", §3.4_

Answer

{'text': 'R/2', 'label': 'B'}

Answer

{'text': '2R', 'label': 'C'}

Answer

{'text': 'R/4', 'label': 'D'}