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Number Systems & Boolean

GATE Electronics & Communication · 59 questions across 31 years (1987-2025) · 78% recurrence rate

Recurrence sparkline

19872025
198720062025

Difficulty mix

easy 68%
med 31%
hard 2%

Question types

MCQ50
OTHER4
NAT3
MSQ2

All 59 questions on Number Systems & Boolean

2025 PYQ

A 3-input majority logic gate has inputs $X, Y$ and $Z$. The output $F$ of the gate is logic ' 1 ' if two or more of the inputs are logic ' 1 '. The output $F$ is logic ' 0 ' if two or more of the inputs are logic '0'. W...

Easy
2024 PYQ

For the Boolean function $F(A, B, C, D) = \sum m(0,2,5,7,8,10,12,13,14,15)$, the essential prime implicants are _________.

Med
2024 PYQ

A machine has a 32-bit architecture with 1-word long instructions. It has 24 registers and supports an instruction set of size 40. Each instruction has five distinct fields, namely opcode, two source register identifiers...

Med
2024 PYQ

In a number system of base $r$, the equation $x^2 - 12x + 37 = 0$ has $x = 8$ as one of its solutions. The value of $r$ is _______.

Easy
2022 PYQ

Consider a Boolean gate (D) where the output Y is related to the inputs A and b as, Y = A + $$\overline B $$, where + denotes logical OR operation. The Boolean inputs '0' and '1' are also available separately. Using inst...

Med
2022 PYQ

Select the Boolean function(s) equivalent to x + yz, where x, y, and z are Boolean variables, and + denotes logical OR operation.

Easy
2020 PYQ

$P, Q$ and $R$ are the decimal integers corresponding to the 4-bit binary number 1100 considered in signed magnitude, 1 's complement and 2 's complement representation, respectively. The 6 -bit 2 's complement represent...

Med
2018 PYQ

A function F(A, B, C) defined by three Boolean variables A, B and C when expressed as sum of products is given by F = $$\overline A .\overline B .\overline C + \overline A .B.\overline C + A.\overline B .\overline C $$ w...

Easy
2017 PYQ

Which one of the following gives the simplified sum of products expression for the Boolean function $$F = {m_0} + {m_2} + {m_3} + {m_5},$$ where $$F = {m_0} + {m_2} + {m_3} + {m_5},$$ are minterms corresponding to the in...

Easy
2017 PYQ

The following five instructions were executed on an 8085 microprocessor. MVI A, 33H MVI B, 78H ADD B CMA ANI 32H The Accumulator value immediately after the execution of the fifth instruction is

Easy
2016 PYQ

The minimum number of 2-input NAND gates required to implement a 2-input XOR gate is

Easy
2015 PYQ

The Boolean expression F(X, Y, Z)= $$\overline X Y\overline Z + X\overline {Y\,} \overline Z + XY\overline Z + XYZ$$ converted into the canonical product of sum (POS)from is

Easy
2015 PYQ

A function of Boolean variables X,Y and Z is expressed in terms of the min-terms as F(X, Y, Z)=$$\sum\limits_{}^{} {} $$m(1,2,5,6,7) Which one of the product of sums given below is equal to the funtion F(X, Y, Z)?

Easy
2015 PYQ

A 3-input majority gate is defined by the logic function M (a,b,c) = ab+bc+ca. Which one of the following gates is represented by the function M$$\left( {\overline {M\left( {a,b,c} \right),} M\left( {a,b,\overline c } \r...

Hard
2014 PYQ

The Boolean expression (X+Y)(X+$$\overline Y $$)+($$\overline {(X\overline Y ) + \overline X } $$ simplifies to

Easy
2014 PYQ

Consider the Boolean function, F(w,z,y,z)=wy+ xy +$$\overline w \,xyz + \overline w \,\overline x y\, + xz + \,\overline {x\,} \,\overline y \,$$ $$\overline z $$ Which one of the following is the complete set of essenti...

Med
2014 PYQ

The number of bytes required to represent the decimal number 1856357 in packed BCD (Binary Coded Decimal) form is __________ .

Easy
2014 PYQ

For an n - variable Boolean function maximum number of prime implicants is

Med
2013 PYQ

In the sum of products function f (x,y,z) = $$\sum {} $$m (2,3,4,5), the prime implicants are

Easy
2013 PYQ

A bulb in a staircase has two switches, one switch being at the ground floor and the other one at the first floor. The bulb can be turned ON and also can be turned OFF by any one of the switches irrespective of the state...

Easy
2010 PYQ

If 137+276=435 how much is 731+672?

Med
2009 PYQ

If X=1 in the logic equation $$\left[ {X + Z\left\{ {\overline Y + (\overline Z + X\overline {Y)} } \right\}} \right]$$ $$\left\{ {\overline X + \overline Z (X + Y)} \right\} = 1,$$ then

Easy
2007 PYQ

An 8085 assembly language program is given below. Line 1: MVI A, B5H 2: MVI B, 0EH 3: XRI 69H 4: ADD B 5: ANI 9BH 6: CPI 9FH 7: STA 3010H 8: HLT The contents of the accumulator just after execution of the ADD instruction...

Med
2007 PYQ

The Boolean expression Y= $$\overline A \,\overline B \,\overline C \,D + \overline A BC\overline D + A\overline {B\,} \overline C \,D + AB\overline C \,\overline D $$

Easy
2007 PYQ

X = 01110 and Y = 11001 are two 5-bit binary numbers represented in two’s complement format. The sum of X and Y represented in two’s complement format using 6 bits is:

Easy
2007 PYQ

The Boolean function Y=AB+CD is to be realized using only 2-input NAND gates. The minimum number of gates required is

Easy
2006 PYQ

A new Binary Coded Pentary (BCP) number system is proposed in which every digit of a base-5 number is represented by its corresponding 3-bit binary code. For example, the base-5 number 24 will be represented by its BCP c...

Easy
2005 PYQ

Decimal 43 in Hexadecimal and BCD number system is respectively

Easy
2005 PYQ

The Boolean expression for the truth table shown is A B C D 0 0 0 0 0 0 1 0 0 1 0 0 0 1 1 1 1 0 0 0 1 0 1 0 1 1 0 1 1 1 1 0

Easy
2004 PYQ

11001, 1001 and 111001 correspond to the 2’s complement representation of which one of the following sets of number?

Easy
2004 PYQ

The Boolean expression AC + B$$\overline C $$ is equivalent to

Easy
2004 PYQ

A Boolean function 'f' of two variables x and y is defined as follows: f(0,0)=f(0,1)=f(1,1)=1;f(1,0)=0 Assuming complements of x and y are not available, a minimum cost solution for realizing F using only 2-input NOR gat...

Med
2004 PYQ

The range of signed decimal numbers that can be represented by 6-bite 1’s complement number is

Easy
2003 PYQ

If the functions W, X, Y and Z are as follows W= R+$$\overline P Q + \overline R $$ S X = $$X = PQ\overline R \,\overline S + \overline P \,\overline Q \,\overline R \,\overline S + P\overline Q \,\overline R \,\overline...

Med
2003 PYQ

The number of distinct Boolean expressions of 4 variables is

Easy
2002 PYQ

4-bit 2’s complement representation of a decimal number is 1000. The number is

Easy
2002 PYQ

The contents of Register (B) and Accumulator (A) of 8085 microprocessor are 49H and 3AH respectively. The contents of A and the status of carry flag (CY) and sign flag (S) after executing SUB B instructions are

Med
2001 PYQ

The 2’s complement representation of –17 is

Easy
1999 PYQ

The Logical expression $$Y = A + \overline A B$$ is equivalent to

Easy
1999 PYQ

The minimized form of the logical expression ($$\overline A \,\overline B \,\overline C + B\overline C + \overline A B\overline C + \overline A BC + AB\overline C )$$

Easy
1999 PYQ

In certain application, four inputs A, B, C, D (both true and complement forms available)are fed to logic circuit, producing an output F which operates a relay. The relay turns on when F(ABCD)=1 for the following states...

Med
1998 PYQ

Two 2' s complement numbers having sign bits x and y added and the sign bit of the result is z. Then, the occurrence of overflow is indicated by the Boolean function.

Easy
1998 PYQ

An equivalent 2’s complement representation of the 2’s complement number 1101 is

Easy
1997 PYQ

A signed integer has been stored in a byte using the 2's complement format. We wish to store the same integer in a 16-bit word. We should

Easy
1996 PYQ

Given the Boolean function F in three variables R, S and T as F=$$\,\overline R \,S\overline T + R\overline {S\,} T + RST$$ (a) Express F in the minimum sum-of-products from. (b) Express F in the minimum product-of-sums...

Med
1995 PYQ

The minimum number of NAND gates required to implement the Boolean function $$A + A\overline B $$ $$ + A\overline B C$$ is equal to

Easy
1995 PYQ

An 'Assembler' for a microprocessor a used for

Easy
1993 PYQ

2’s complement representation of a 16-bit number (one sign bit and 15 magnitude bits) is FFFI. Its magnitude in decimal representation is

Easy
1993 PYQ

Boolean expression for the output of XNOR (equivalence) logic gate with inputs A and B is

Easy
1992 PYQ

A combinational circuit has three inputs A, B and C and an output F. F is true only for the following input combinations? A is false and B is true A is false and C is true A, B and C are all false A, B and C are all true...

Med
1991 PYQ

The four variable function f is given in terms of min-terms as: f (A B C D ) = $$\sum {} $$m (2,3,8,10,11,12,14,15 .) Using the K-map minimize the function in the sum of products form. Also, given the realization using o...

Med
1990 PYQ

The number of Boolean functions that can be generated by n variable is equal to:

Easy
1990 PYQ

The minimum function that can detect a "divisible by 3" 8421 BCD code digit (representation is D 8 D 4 D 2 D 1 ) is given by:

Med
1989 PYQ

Indicate which of the following logic gates can be used to realize all possible combinational Logic functions:

Easy
1988 PYQ

The minimum number of 2-input NAND gates required to implement the Boolean function Z=A$$\overline {B\,} $$C, assuming that A, B and C are available, is

Med
1988 PYQ

The Boolean function A+BC is a reduced form of

Easy
1988 PYQ

Minimum number of 2-input NAND gates required to implement the function, f=($$\overline X $$+$$\overline Y $$)(Z+W) is

Med
1988 PYQ

For the identity AB+$$\overline A $$ C + BC= AB + $$\overline A $$ C, The dual form is

Easy
1987 PYQ

The subtraction of a binary number Y from another binary number X, done by adding the 2's complement of Y to X, result in a binary number without overflow. This implies that the result is:

Easy