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JEE Main 202622 JanuaryMorning Shift
Exam
JEE Main
Year
2026
Date
22 January
Shift
Morning Shift
Subject
Physics
Chapter
Current Electricity

JEE Main 2026 · 22 January · Morning Shift · Physics · Current Electricity

A meter bridge with two resistances R_ 1 and R_ 2 as shown in...

A meter bridge with two resistances R1R_{1} and R2R_{2} as shown in figure was balanced (null point) at 40 cm from the point PP. The null point changed to 50 cm from the point PP, when 16Ω16 \Omega resistance is connected in parallel to R2R_{2}. The values of resistances R1R_{1} and R2R_{2} are ____\_\_\_\_.
A meter bridge with two resistances R_ 1 and R_ 2 as shown in figure was balanced (null point) at 40 cm from the point

Options

  1. AR2=4Ω,R1=43ΩR_{2}=4 \Omega, R_{1}=\frac{4}{3} \Omega
  2. BR2=16Ω,R1=163ΩR_{2}=16 \Omega, R_{1}=\frac{16}{3} \Omega
  3. CR2=12Ω,R1=123ΩR_{2}=12 \Omega, R_{1}=\frac{12}{3} \Omega
  4. DR2=8Ω,R1=163ΩR_{2}=8 \Omega, R_{1}=\frac{16}{3} \Omega

Correct answer

D. R2=8Ω,R1=163ΩR_{2}=8 \Omega, R_{1}=\frac{16}{3} \Omega

Step-by-step solution

Initial balance at 40 cm: R1R2=4060=23\frac{R_1}{R_2} = \frac{40}{60} = \frac{2}{3} ...(i)
With 16 Ω16\,\Omega parallel to R2R_2, null point at 50 cm:
R116R216+R2=5050=1⇒R1=16R216+R2\frac{R_1}{\frac{16R_2}{16+R_2}} = \frac{50}{50} = 1 \Rightarrow R_1 = \frac{16R_2}{16+R_2} ...(ii)
From (i): R1=23R2R_1 = \frac{2}{3}R_2.
Substituting in (ii): 23R2=16R216+R2\frac{2}{3}R_2 = \frac{16R_2}{16+R_2}.
23=1616+R2⇒2(16+R2)=48⇒R2=8 Ω\frac{2}{3} = \frac{16}{16+R_2} \Rightarrow 2(16+R_2) = 48 \Rightarrow R_2 = 8\,\Omega.
R1=163 ΩR_1 = \frac{16}{3}\,\Omega.
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