Question:

For Boolean variables A and B, \( A \oplus B = A\bar{B} + \bar{A}B \). Then, which of the following statements is/are correct?

Show Hint

XOR is a "difference detector". It outputs 1 only when the two inputs are different:
- \( A \oplus A \): Inputs are identical, so output is always 0 (Statement B is correct).
- \( A \oplus \bar{A} \): Inputs are always opposite, so output is always 1 (Statement D is correct).
- \( 1 \oplus A \): Output is the invert of \( A \) (Statement A is correct).
This conceptual shortcut avoids algebraic derivations.
Updated On: May 28, 2026
  • \( 1 \oplus A = \bar{A} \)
  • \( A \oplus A = 0 \)
  • \( 0 \oplus A = 0 \)
  • \( A \oplus \bar{A} = 1 \)
Show Solution
collegedunia
Verified By Collegedunia

The Correct Option is A

Solution and Explanation

Step 1: Understanding the Question:
The problem defines the XOR (exclusive OR) operation \( \oplus \) for Boolean variables and asks us to identify the correct statements from the given algebraic identities.

Step 2: Key Formula or Approach:

We will evaluate the XOR expression \( X \oplus Y = X\bar{Y} + \bar{X}Y \) for each statement using basic Boolean algebra laws:
- Identity law: \( X \cdot 1 = X \) and \( X \cdot 0 = 0 \)
- Complementarity law: \( X \cdot \bar{X} = 0 \) and \( X + \bar{X} = 1 \)
- Involution (Double Negation): \( \overline{(\bar{X})} = X \)

Step 3: Detailed Explanation:

Let's check each statement:
- Option (A): \( 1 \oplus A \)
\[ 1 \oplus A = 1 \cdot \bar{A} + \bar{1} \cdot A \]
Since \( \bar{1} = 0 \):
\[ 1 \oplus A = \bar{A} + 0 \cdot A = \bar{A} \]
This statement is correct.
- Option (B): \( A \oplus A \)
\[ A \oplus A = A \cdot \bar{A} + \bar{A} \cdot A \]
Since \( A \cdot \bar{A} = 0 \):
\[ A \oplus A = 0 + 0 = 0 \]
This statement is correct.
- Option (C): \( 0 \oplus A \)
\[ 0 \oplus A = 0 \cdot \bar{A} + \bar{0} \cdot A \]
Since \( \bar{0} = 1 \):
\[ 0 \oplus A = 0 + 1 \cdot A = A \]
The option states \( 0 \oplus A = 0 \), which is incorrect.
- Option (D): \( A \oplus \bar{A} \)
\[ A \oplus \bar{A} = A \cdot \overline{(\bar{A})} + \bar{A} \cdot A \]
Since \( \overline{(\bar{A})} = A \):
\[ A \oplus \bar{A} = A \cdot A + 0 = A + \bar{A} = 1 \]
This statement is correct.

Step 4: Final Answer:

The correct statements are (A), (B), and (D).
Was this answer helpful?
0
0