Question

Below we give four entries for the truth table of two point input OR gate. Which two are wrong?
\(\begin{aligned} & A & B & Y \\ \text{i} & 1 & 0 & 1 \\ \text{ii} & 1 & 1 & 0 \\ \text{iii} & 0 & 0 & 1 \\ \text{iv} & 0 & 1 & 1 \end{aligned}\)

• A. (i) and (ii)
• B. (ii) and (iii)
• C. (iii) and (iv)
• D. (iv) and (i)

Hint:

An OR gate outputs 0 only when both inputs are 0; in every other case it outputs 1.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept
The OR gate has output \(Y=A+B\). It gives 1 if at least one input is 1 and 0 only for the input pair 0, 0.

Step 2: Check each entry
(i) 1, 0 gives 1: correct.
(ii) 1, 1 should give 1 but 0 is shown: wrong.
(iii) 0, 0 should give 0 but 1 is shown: wrong.
(iv) 0, 1 gives 1: correct.

Step 3: Conclusion
The wrong entries are (ii) and (iii).

Final Answer:
Entries (ii) and (iii) are wrong. \[ \boxed{\text{(B) }\text{(ii) and (iii)}} \]