This set of Digital Electronics/Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Boolean Logic Operations”.

1. In boolean algebra, the OR operation is performed by which properties?

a) Associative properties

b) Commutative properties

c) Distributive properties

d) All of the Mentioned

View Answer

Explanation: The expression for Associative property is given by A+(B+C) = (A+B)+C & A*(B*C) = (A*B)*C.

The expression for Commutative property is given by A+B = B+A & A*B = B*A.

The expression for Distributive property is given by A+BC=(A+B)(A+C) & A(B+C) = AB+AC.

2. The expression for Absorption law is given by _________

a) A + AB = A

b) A + AB = B

c) AB + AA’ = A

d) A + B = B + A

View Answer

Explanation: The expression for Absorption Law is given by: A+AB = A.

Proof: A + AB = A(1+B) = A (Since 1 + B = 1 as per 1’s Property).

3. According to boolean law: A + 1 = ?

a) 1

b) A

c) 0

d) A’

View Answer

Explanation: A + 1 = 1, as per 1’s Property.

4. The involution of A is equal to _________

a) A

b) A’

c) 1

d) 0

View Answer

Explanation: The involution of A means double inversion of A (i.e. A”) and is equal to A.

Proof: ((A)’)’ = A

5. A(A + B) = ?

a) AB

b) 1

c) (1 + AB)

d) A

View Answer

Explanation: A(A + B) = AA + AB (By Distributive Property) = A + AB (A.A = A By Commutative Property) = A(1 + B) = A*1 (1 + B = 1 by 1’s Property) = A.

6. DeMorgan’s theorem states that _________

a) (AB)’ = A’ + B’

b) (A + B)’ = A’ * B

c) A’ + B’ = A’B’

d) (AB)’ = A’ + B

View Answer

Explanation: The DeMorgan’s law states that (AB)’ = A’ + B’ & (A + B)’ = A’ * B’, as per the Dual Property.

7. (A + B)(A’ * B’) = ?

a) 1

b) 0

c) AB

d) AB’

View Answer

Explanation: The DeMorgan’s law states that (AB)’ = A’ + B’ & (A + B)’ = A’ * B’, as per the Dual Property.

8. Complement of the expression A’B + CD’ is _________

a) (A’ + B)(C’ + D)

b) (A + B’)(C’ + D)

c) (A’ + B)(C’ + D)

d) (A + B’)(C + D’)

View Answer

Explanation: (A’B + CD’)’ = (A’B)'(CD’)’ (By DeMorgan’s Theorem) = (A” + B’)(C’ + D”) (By DeMorgan’s Theorem) = (A + B’)(C’ + D).

9. Simplify Y = AB’ + (A’ + B)C.

a) AB’ + C

b) AB + AC

c) A’B + AC’

d) AB + A

View Answer

Explanation: Y = AB’ + (A’ + B)C = AB’ + (AB’)’C = (AB’ + C)( AB’ + AB’) = (AB’ + C).1 = (AB’ + C).

10. The boolean function A + BC is a reduced form of ____________

a) AB + BC

b) (A + B)(A + C)

c) A’B + AB’C

d) (A + C)B

View Answer

Explanation: (A + B)(A + C) = AA + AC + AB + BC = A + AC + AB + BC (By Commutative Property) = A(1 + C + B) + BC = A + BC (1 + B + C =1 By 1’s Property).

**Sanfoundry Global Education & Learning Series – Digital Circuits.**

To practice all areas of Digital Circuits, __here is complete set of 1000+ Multiple Choice Questions and Answers__.