Q 12-03-092JEE MainJEE Main 2024 (29 Jan, Shift 2)Easy
In the given circuit, the current flowing through the resistance $20\ \Omega$ is $0.3\ \text{A}$, while the ammeter reads $0.9\ \text{A}$. The value of $R_1$ is ______ $\Omega$.
Numerical value type. Enter your answer.
Answer: 30
Voltage across the parallel combination: $V = 0.3\times20 = 6\ \text{V}$.
Current in $15\ \Omega$: $\dfrac{6}{15} = 0.4\ \text{A}$. Current in $R_1$: $0.9 - 0.3 - 0.4 = 0.2\ \text{A}$.
$$R_1 = \frac{6}{0.2} = 30\ \Omega$$
Solution by Sreeraj P, M.Sc Physics