JEE Physics 2025 Question with Solution

Given: $R_1 = R_2 = R_3 = 5 \, \Omega$ and $R_4 = 10 \, \Omega$.

Find: Which circuit gives equivalent resistance $6 \, \Omega$.

From the solution, the correct selection is stated to be Option A. The required principle is combination of resistors in series and parallel.

For the first option, the top branch has $R_1$ and $R_2$ in series, and the bottom branch has $R_3$ and $R_4$ in series. Therefore,

and

These two branches are in parallel, so

Therefore, the circuit in Option A gives the required equivalent resistance of $6 \, \Omega$. The correct option is A.

Given: $R_1 = R_2 = R_3 = 5 \, \Omega$ and $R_4 = 10 \, \Omega$.

Find: The option whose equivalent resistance is $6 \, \Omega$.

Use the standard formulas:

The solution explicitly states that the first option gives the desired equivalent resistance of $6 \, \Omega$ and concludes, "Thus, the correct answer is (1)." This maps to A.