JEE Physics 2025 Question with Solution

Given: A logic circuit with inputs $X$ and $Y$ is shown.

Find: For which input combinations the output is low, i.e. $0$.

From the solution, the circuit behaves as a NAND gate followed by a NOT gate. Therefore, the final output is the inversion of the NAND output.

Check each case:

• For $X = 0, Y = 0$:

So the output is low.

• For $X = 0, Y = 1$:

So the output is low.

• For $X = 1, Y = 0$:

So the output is low.

• For $X = 1, Y = 1$:

So the output is high.

Therefore, the output is low for (A), (B) and (C) only. The correct option is A.

Given: Input pairs are labeled as (A), (B), (C) and (D).

Find: Which labels produce final output $0$.

Using the gate behavior stated in the solution:

Hence, the low output occurs for (A), (B) and (C) only. So the correct option is A.

The solution contains inconsistent wording in one approach about gate names, but both approaches conclude the same valid set of inputs and the same correct option.