The output of a two input NOR gate is in state 1 when :-

Options

A. either input terminals is at 0 state
B. either input terminals is at 1 state
C. both input terminals are at 0 state
D. both input terminals are at 1 state

Answer

To determine when the output of a two-input NOR gate is in state 1, we can follow these steps:

### Step 1: Understand the NOR Gate
A NOR gate is a digital logic gate that outputs true or 1 only when both of its inputs are false or 0.

### Step 2: Write the Boolean Expression
The output \( y \) of a two-input NOR gate can be expressed using the Boolean expression:
\[ y = (A + B)' \]
where \( A \) and \( B \) are the inputs and the apostrophe (') denotes the NOT operation.

### Step 3: Create a Truth Table
We can create a truth table to analyze the output based on all possible combinations of the inputs \( A \) and \( B \):

| A | B | A + B | (A + B)' (Output y) |
|---|---|-------|---------------------|
| 0 | 0 | 0 | 1 |
| 0 | 1 | 1 | 0 |
| 1 | 0 | 1 | 0 |
| 1 | 1 | 1 | 0 |

### Step 4: Analyze the Truth Table
From the truth table, we can see that the output \( y \) is 1 only when both inputs \( A \) and \( B \) are 0. Therefore, the output of the NOR gate is in state 1 only when both inputs are at 0.

### Step 5: Conclusion
Thus, the output of a two-input NOR gate is in state 1 when both input terminals are at 0 state.

### Final Answer
The correct answer is: The output of a two-input NOR gate is in state 1 when both input terminals are at 0 state.

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