COMEDK · Physics · 19. Current Electricity
A resistor of wire \(24 \mathrm{~cm}\) length and resistance \(8 \Omega\) is stretched in to a uniform wire of \(48 \mathrm{~cm}\) length, then the new resistance will be :
- A \(4 \Omega\)
- B \(8 \Omega\)
- C \(16 \Omega\)
- D \(32 \Omega\)
Answer & Solution
Correct Answer
(D) \(32 \Omega\)
Step-by-step Solution
Detailed explanation
The resistance \(R\) of a wire is given by \(R = \rho \dfrac{l}{A}\), where \(\rho\) is the resistivity, \(l\) is the length, and \(A\) is the cross-sectional area. Since the volume \(V = A \times l\) of the wire remains constant during stretching, we have \(A_1 l_1 = A_2 l_2\).…
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