Operational condition for NOR: For a multi-input NOR gate, under which input condition will the output be 0 (LOW)?

Introduction / Context:
For reliable logic design, one must know the precise conditions for NOR outputs. NOR is widely used in active-low logic and for functionally complete implementations.

Given Data / Assumptions:

• NOR = NOT(OR).
• Inputs can be any combination of 0 and 1.

Concept / Approach:
If any input is 1, OR outputs 1. Inverting that, NOR outputs 0 whenever at least one input is 1. NOR outputs 1 only when all inputs are 0.

Step-by-Step Solution:
1) Evaluate OR for input pattern.2) Invert to get NOR.3) Conclude output 0 occurs whenever any input = 1.

Verification / Alternative check:
Construct a truth table for a two-input NOR; generalizes to n-input.

Why Other Options Are Wrong:
“Whenever a 0…” contradicts NOR; “Only when all inputs = 0” is NOR = 1 case; “Only when all inputs = 1” is not special for NOR output 0 because any single 1 already forces 0.

Common Pitfalls:
Confusing NOR with NAND; mixing up the OR trigger condition.

Final Answer:
Whenever a 1 is present at an input