Kirchhoff's Laws & Measuring Instruments question from JEE Main 2014 (11 Apr, Shift 1)

Answer: (c)

1. Left rails: top $50$ V, bottom $0$. Right rails: top $a$, bottom $b$ with $a - b = 30$ V.
2. The two $5\ \Omega$ carry the same current: $\frac{50 - a}{5} = \frac{b}{5} \Rightarrow a + b = 50$, so $a = 40$, $b = 10$, current $= 2$ A.
3. $10\ \Omega$: $\frac{30}{10} = 3$ A, so the $30$ V battery gives $3 - 2 = 1$ A.
4. $20\ \Omega$: $\frac{50}{20} = 2.5$ A, so the $50$ V battery gives $2.5 + 2 = 4.5$ A.
5. So the answer is (c) 4.5 and 1.