Exams › NEET › Physics

In the figure, two metal wires of identical dimension are connected in series. Find the equivalent resistance.

1. Req = l / σ1A + l / σ2A
2. Req = 2l / σeqA
3. σeq = 2σ1σ2 / σ1 + σ2
4. σeq = σ1σ2 / σ1 + σ2

Correct answer: Req = 2l / σeqA

Solution

When two resistors are connected in series, their resistances add up. The resistance of a wire is given by R = l / (σA). For two wires in series, the equivalent resistance is Req = l / σ1A + l / σ2A, which simplifies to Req = 2l / σeqA.

Related NEET Physics questions

• For a metallic wire, the ratio \( \frac{V}{i} \) (where, \( \mathbf{V}= \) applied potential difference and \( \mathbf{i}= \) current flowing
• In a metallic conductor, electric current is thought to be due to the movement of
• Assertion If the length of the conductor is doubled, the drift velocity will become half of the original value (keeping potential difference unchanged). Reason At constant potential difference, drift velocity is inversely proportional to the length of the conductor.
• The resistance of an iron wire is \( 10 \Omega \) and its temperature coefficient of resistance is \( 5 \times 10^{-3} /^{o} C . \) A current of \( 30 \mathrm{mA} \) is flowing in it at \( 20^{\circ} \mathrm{C} \). Keeping potential difference across its ends constant, if its temperature is increased to \( 120^{\circ} \mathrm{C} \) then the current flowing in the wire will be (in \( \mathrm{mA} \) )
• Wire of a certain material is stretched slowly be dep10. Its new resistance and specific resistance becomes respectively.
• Which of the following statements are wrong w.r.t the specific resistance of wire? This question has multiple correct options

⚔️ Practice NEET Physics free + battle 1v1 →