A digital circuit can be constructed by the repeated use of which of the following universal logic gates?
Both NAND and NOR gates are universal gates because any Boolean function can be implemented using only NAND gates or only NOR gates.
An OR gate has 4 inputs. How many rows will be present in its truth table?
The number of rows in a truth table for n binary inputs is $2^n$. For n = 4 inputs, 2^4 = 16 rows.
What is De Morgan's theorem primarily used for in digital logic circuits?
De Morgan's theorems ((A.B)' = A' + B' and (A+B)' = A'.B') provide mathematical rules for simplifying complex Boolean expressions and logic circuits.
According to the Boolean Absorption Law, what is the simplified form of the expression A + AB?
By the Absorption Law: A + AB = A(1 + B). Since 1 + B = 1 in Boolean algebra, A(1) = A.
What is the minimum number of 2-input NAND gates required to implement a 2-input XOR gate?
A 2-input XOR gate requires exactly 4 NAND gates. A 2-input XNOR gate requires 5 NAND gates.