Physics · Current Electricity

JEE Main 2025 — 7 April, Morning Shift — Question 65

A wire of resistance $R$ is bent into a triangular pyramid as shown in figure with each segment having same length. The resistance between points $A$ and $B$ is $R / n$ . The value of $n$ is

Option A:
10
Correct
Option B:
12
Option C:
16
Option D:
14

Answer: A

Step-by-step solution

Clearly, $R_{1}=\frac{R}{6}$ So $R_{A B}=R_{1}\left\|2 R_{1}\right\| 2 R_{1}$

$\Rightarrow \frac{1}{R_{A B}}=\frac{1}{R_{1}}+\frac{1}{2 R_{1}}+\frac{1}{2 R_{1}}=\frac{4}{2 R_{1}}=\frac{2}{R_{1}}$

$\Rightarrow \quad R_{A B}=\frac{R_{1}}{2}=\frac{R}{12}$

Answer key and solution verified before publishing.

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Exam: JEE Main 2025
Paper: 7 April, Morning Shift
Subject: Physics
Chapter: Current Electricity
Topic: Combination of Resistors and cells, Wheatstone Bridge