Which gate outputs high if any input is true?

Which gate outputs high if any input is true?

• A. And Gate
• B. Not Gate
• C. Nand Gate
• D. Or Gate

Answer: (D)

This question tests how an OR gate behaves: its output goes high whenever any input is true. For a two-input OR, if both inputs are false, the output is false; if either input is true (or both are true), the output is true. That matches the idea of “any input is true.” Think of it like a light controlled by multiple switches: flip any switch to turn the light on. An AND gate would need all switches on to light the lamp, a NOT gate would invert a single input, and a NAND gate would be on except when all inputs are on. So the behavior described—outputting high when any input is true—fits the OR gate.

This question tests how an OR gate behaves: its output goes high whenever any input is true. For a two-input OR, if both inputs are false, the output is false; if either input is true (or both are true), the output is true. That matches the idea of “any input is true.”

Think of it like a light controlled by multiple switches: flip any switch to turn the light on. An AND gate would need all switches on to light the lamp, a NOT gate would invert a single input, and a NAND gate would be on except when all inputs are on. So the behavior described—outputting high when any input is true—fits the OR gate.