COMEDK · Physics · 19. Current Electricity
The resistance of a wire is 5 ohm at \(25^{\circ} \mathrm{C}\) and 7 ohm at \(100^{\circ} \mathrm{C}\). The resistance of the wire at \(0^{\circ} \mathrm{C}\) is
- A 0.1 ohm
- B \(\dfrac{2}{3} \mathrm{ohm}\)
- C \(\dfrac{5}{3} \mathrm{ohm}\)
- D \(\dfrac{13}{3} \mathrm{ohm}\)
Answer & Solution
Correct Answer
(D) \(\dfrac{13}{3} \mathrm{ohm}\)
Step-by-step Solution
Detailed explanation
The resistance of a wire at temperature \(t\) is given by the formula \(R_t = R_0(1 + \alpha t)\), where \(R_0\) is the resistance at \(0^{\circ} \mathrm{C}\) and \(\alpha\) is the temperature coefficient of resistance. Given \(R_{25} = 5 \, \Omega\) at \(25^{\circ} \mathrm{C}\)…
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