Choose the logic operation carried out by the following circuit:

The correct answer is Option (2) → AND Gate

All three gates are NOR gates. The first two have both inputs joined together, and a NOR gate with joined inputs works as a NOT gate:

    \( \displaystyle \overline{A + A} = \bar{A}, \qquad \overline{B + B} = \bar{B} \)

These outputs \( \bar{A} \) and \( \bar{B} \) are the inputs of the last NOR gate:

    \( \displaystyle Y = \overline{\bar{A} + \bar{B}} \)

By De Morgan's theorem, \( \overline{X + Z} = \bar{X}\cdot\bar{Z} \), so

    \( \displaystyle Y = \bar{\bar{A}}\cdot\bar{\bar{B}} = A\cdot B \)

This is the Boolean expression of an AND gate.

    \( A = 0,\ B = 0:\ Y = 0 \)
    \( A = 0,\ B = 1:\ Y = 0 \)
    \( A = 1,\ B = 0:\ Y = 0 \)
    \( A = 1,\ B = 1:\ Y = 1 \)

Note: This question is from the pre-rationalised NCERT book (2022-23). The topic was removed from the latest NCERT book (2026-27), and it also appears to be out of the CUET 2026 syllabus.

NCERT (Pre-rationalised edition, 2022-23):
Exercises – …