ITPEC IP April 2024 Question 2

AND — the output is 1 only in the row where both A and B are 1.

Compare the output column with the truth table of each two-input operation:

Only the AND column matches in every row: the result is true only when both inputs are true.

Answer (a)

Why not others:

• •(b) NOT — has a single input and inverts it; NOT A would give 1, 1, 0, 0, and no one-input operation can produce this table
• •(c) OR — outputs 1 when at least one input is 1, giving 0, 1, 1, 1
• •(d) XOR — outputs 1 when the inputs differ, giving 0, 1, 1, 0

Key rule: Identify a two-input operation by its 1s: AND has one (both inputs 1), OR has three (at least one input 1), XOR has two (inputs differ); NAND, NOR and NOT XOR are the same tables inverted.

Basic Theory · AI-written, may contain errors