Physics Circle home Student Login

Home›Chapters›Current Electricity PYQs›Combination of Resistors›Question 6

JEE Main 2026 (24 Jan, Shift 2) · Combination of Resistors

Combination of Resistors question from JEE Main 2026 (24 Jan, Shift 2)

Q6JEE Main 2026 · 24 JAN · SHIFT 2Difficult

Combination of Resistors

A regular hexagon is formed by six wires each of resistance r Ωr\ \Omega and the corners are joined to the centre by wires of same resistance. If the current enters at one corner and leaves at the opposite corner, the equivalent resistance of the hexagon between the two opposite corners will be

Show answer and solution

Answer: (b)

  1. Number corners 1 to 6, current in at 1, out at 4. Take V1=1V_1 = 1, V4=0V_4 = 0; by symmetry centre =12= \tfrac12, V2=V6=xV_2 = V_6 = x, V3=V5=1−xV_3 = V_5 = 1 - x.
  2. KCL at 2: (x−1)+(x−(1−x))+(x−12)=0⇒x=58(x - 1) + (x - (1-x)) + (x - \tfrac12) = 0 \Rightarrow x = \tfrac58
  3. Current from 1 (in units of 1/r1/r): 2(1−58)+12=542\left(1 - \tfrac58\right) + \tfrac12 = \tfrac54
  4. Req=15/4 r=45rR_{eq} = \dfrac{1}{5/4}\,r = \dfrac{4}{5}r. So the answer is (b).
Report a mistake

More questions on Combination of Resistors