CBSE 2025 · Region 7 · Set 1 · Q22 · 3 marks
Three cells $\displaystyle \mathrm{A}, \mathrm{B}$ and C of emfs $\displaystyle 2 \mathrm{~V}, 3 \mathrm{~V}$ and $\displaystyle 5$ V respectively are connected in parallel to each other. Their internal resistances are $\displaystyle 5 \Omega, 5 \Omega$ and $\displaystyle 1 \Omega$ respectively. Calculate the currents flowing through the cells $\displaystyle \mathrm{A}, \mathrm{B}$ and C .
Marking-scheme solution
In loop ABEFA,\[5 - 3 - 5I_1 - I = 0\]
\[2 = 5I_1 + I \qquad ----- (1)\]In loop CBEDC,\[2 - 3 - 5I_1 + 5I - 5I_1 = 0\]
\[-1 = 10I_1 - 5I \qquad ----- (2)\]Solving equation ($\displaystyle 1$) and ($\displaystyle 2$)$\displaystyle I = \dfrac{5}{7}\,\text{A}$ in arm AF/through the cell of 5V(A)$\displaystyle I_1 = \dfrac{9}{35}\,\text{A}$ in arm BE/through the cell of 3V(B)$\displaystyle I - I_1 = \dfrac{16}{35}\,\text{A}$ in arm CD/through the cell of 2V(C)Current ElectricityCells in Series and in ParallelApplyshort_answermedium
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