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JEE Main 2026 · 5 Apr · Shift 1, Physics question 34

Refer to the figure given below. The values of I1I_1, I2I_2 and I3I_3 are ________.

Diamond network with left, top, bottom and right corners. Left-top: 4 Ω. Left-bottom: 4 Ω (current I₃). A vertical wire from top to bottom carries two 2 Ω resistors with a midpoint between them; the left corner connects to that midpoint through a 10 V cell and a 1 Ω resistor (current I₁). The top and bottom corners are also joined through the right corner by wires containing a 5 V cell and no resistance (current I₂).
Choose one option
Answer and worked solution

Official answer: A

Node potentials. Call the corners L (left), T (top) and B (bottom), and the midpoint of the vertical wire M.

  • The 5 V cell joins T and B through wires with no resistance, so take VB=0V_B=0, VT=5V_T=5 V.
  • The 10 V cell has its positive terminal towards L, so in the L-M branch VL=VM+10−I1(1)V_L=V_M+10-I_1(1), with I1I_1 flowing from M to L.

KCL at M.
5−VM2+0−VM2=I1.\frac{5-V_M}2+\frac{0-V_M}2=I_1.

KCL at L.
VL−54+VL4=I1.\frac{V_L-5}4+\frac{V_L}4=I_1.

Solving. These give VM=0V_M=0, VL=7.5V_L=7.5 V and I1=2.5I_1=2.5 A.

Branch currents.

  • I3=7.5−04=1.875I_3=\dfrac{7.5-0}4=1.875 A.
  • Into T from L: 2.54=0.625\dfrac{2.5}4=0.625 A. Out of T through the upper 2 Ω: 52=2.5\dfrac52=2.5 A.
  • So the 5 V branch supplies I2=2.5−0.625=1.875I_2=2.5-0.625=1.875 A.

(A)