The truth table of logic gate is:
| Input | Output | |
|---|---|---|
| A | B | Y |
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 0 |
The correct logic symbol for the truth table is:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2)
The output Y is 1 only when both inputs are 0, and 0 in every other case. This is an OR operation followed by NOT, that is, the NOR gate, \( Y = \overline{A+B} \). Its symbol is the OR gate with a small circle (the NOT) at the output.
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):
Logic Gates – “… It has two or more inputs and one output. A NOT- operation applied after OR gate gives a NOT-OR gate (or simply NOR gate). Its output Y is ’1’ only when both inputs A and B are ’0’, i.e., neither one input nor the other is ’1’. The symbol and truth table for NOR gate is given in Fig. 14.42.”
