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JEE Main 2024 (9 Apr, Shift 1) · Kirchhoff's Laws & Measuring Instruments

Kirchhoff's Laws & Measuring Instruments question from JEE Main 2024 (9 Apr, Shift 1)

Q58JEE Main 2024 · 9 APR · SHIFT 1Medium

Kirchhoff's Laws & Measuring Instruments

The current flowing through the 1 Ω1\ \Omega resistor is n10\frac{n}{10} A. The value of nn is _______.

Figure

Numerical answer type. Work it out, then open the answer.

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Answer: 25

  1. Take VA=0V_A = 0. The 5 V cell gives VB−VD=5V_B - V_D = 5; current in the 1 Ω1\ \Omega branch C to A is I1=VC+10I_1 = V_C + 10.
  2. KCL for the B+D pair: VB+VD4=2VC−VB−VD2⇒VC=34(VB+VD)\frac{V_B + V_D}{4} = \frac{2V_C - V_B - V_D}{2} \Rightarrow V_C = \frac{3}{4}(V_B + V_D)
  3. KCL at C: VB+VD−2VC2=VC+10⇒VB+VD=−10\frac{V_B + V_D - 2V_C}{2} = V_C + 10 \Rightarrow V_B + V_D = -10, VC=−7.5 VV_C = -7.5\text{ V}
  4. I1=−7.5+10=2.5 A=2510 AI_1 = -7.5 + 10 = 2.5\text{ A} = \frac{25}{10}\text{ A}
  5. So n=25n = 25.
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