NCERT Exercise 11.1 — Q6 - Electricity
Question: A copper wire has diameter 0.5 mm and resistivity of 1.6 × 10⁻⁸ Ω·m. What will be the length of this wire to make its resistance 10 Ω? How much does the resistance change if the diameter is doubled?
Answer: Length ≈ **122.5 m**. If diameter is doubled, resistance becomes **2.5 Ω** (one-fourth of 10 Ω).
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