Q 12-03-200JEE MainJEE Main 2021 (20 Jul, Shift 1)Medium
The value of current in the $6\ \Omega$ resistance is:
Answer: (C) 10 A
Take the bottom wire as 0 V and let the top junction be at $V$. Kirchhoff's current law at the junction:
$$\frac{140 - V}{20} + \frac{90 - V}{5} = \frac{V}{6}$$
Multiply by 60: $420 - 3V + 1080 - 12V = 10V \Rightarrow V = 60$ V.
Current in $6\ \Omega$: $\dfrac{60}{6} = 10$ A.
Solution by Sreeraj P, M.Sc Physics