engineering physics MCQ #955

The resistance of a wire is 10 ohms. If it is stretched to double its length, its new resistance will be

engineering physics MCQ #955

  1. Question 1

    Q1. The resistance of a wire is 10 ohms. If it is stretched to double its length, its new resistance will be

    • A) 40 ohms
    • B) 20 ohms
    • C) 10 ohms
    • D) 5 ohms

    Answer: 40 ohms

    Explanation: Resistance is directly proportional to length and inversely to area. When length doubles, area halves, so R = ρ(2l)/(A/2) = 4ρl/A = 4R.