STLD
FIRST MID JNTUH ONLINE BITS
UNIT-1(Number systems and
codes)
Section-I : choose the correct answer
1. The fraction (0.68)10 is equal
to [ ]
a) (0.010101)2 b) (0.101)2 c)
(0.10101)2
d) (0.10111)2
2.
The Hexadecimal number A0 has the decimal value [ ]
a)80 b) 256 c) 100 d) 160
3.
Given two numbers A & B in sign magnitude representation in an eight bit
format A=00011110 & B=10011100, A
XOR B gives [ ]
a)10000010
b) 00011111 c) 10011101 d) 11100001
4.
The value of binary 1111 is [ ]
a) 23-1 b) 24-1 c) 24 d)
none of these
5. The minimum number of bits required to
represent negative numbers in the range of -1 to -11 using 2’s complement
arithmetic is [ ]
(a)2 (b) 3 (c) 4 (d) 5
6. The following code is not a BCD code. [ ]
a)Gray code (b) Xs-3 code (c) 8421 code (d)
All of these
7. A 15-bit hamming code requires [ ]
(a)4 parity bits
(b) 5 parity bits (c) 15 parity bits (d) 7 parity bits
8.If=5,the base(radix) of the number system is
[ ]
a)5 (b) 6 (c) 7 (d) 8
9. The hexadecimal number system is used in digital computers and
digital systems to [ ]
(a) Perform arithmetic operations (b)
Perform logic operations
(c) Perform
arithmetic and logic operations (d) Input binary data into the sys
10. Determine the value of base x
if : (211)x = (152)8 [ d]
(a) 2 (b) 10 (c)
8 (d) 7
11. Determine the value of base
x, if (193)x
= (623)8 [a ]
(a)16 (b)4 (c)2
(d)5
12. Which of the following are
called Universal gates [ a]
(a) NAND,NOR (b)
AND,OR (c) XOR XNOR (d) OR,XOR
Section-II: Fill in the blanks
18. Cyclic codes are also called ________________codes
19. The basic two types of BCD codes are _______________and________
codes.
20. The distance between code words 10010 & 10101 is ________.
21. Convert the binary code (110110)2 to Gray code 101101
22. Conversion of 0.1289062 decimal number to its hexa equivalent is (0.21)16
23. In b’s complement method, the carry is Ignored and in(b-1)’s complement method the carry
is add to the LSD
24. The MSB of a binary number has a weight of 512,the number consists
of 10 bits bits.
25. Alpha numeric codes are
codes which represent letters of the alphabets and decimal numbers as a sequence of 0s and 1s.
UNIT-2(Boolean algebra and
switching functions)
1.The short hand notation of
min term m6
is [ d]
(a) (b) (c) ABC (d) 
2. In Boolean algebra A+AB= A
3. Boolean expression xy+yz+ = xy+z
on reduction.
4. The given expression Y=A+AB+ABC in SOP form is ABC+A+AB+AC
Unit-3(minimization
of switching functions)
1. In K-map each of the cell represents one of the _________ possible
products [ a ]
(a)2n (b)2-n (c)n2 (d)All
the above
Unit-4(combinational
logic designs)
1. The serial adder is a
___________circuit, the parallel adder is a ___________ circuit excluding the
registers [d ]
(a)sequential, sequential (b)combinational, sequential
(c)combinational,
combinational (d) sequential, combinational
2. Which of the following are
called Universal gates a[a ]
(a) NAND,NOR
(b) AND,OR (c) XOR XNOR (d) OR,XOR
3. Which of the following
circuits can be used as parallel-to-serial converter [c ]
(a)digital
counter (b)decoder (c)multiplexer (d)demultiplexer
STLD
feb 2012 paper
1. The minimum
number of bits required to represent negative numbers in the range of -1 to -11
using 2’s complement arithmetic is [d ]
(a)2 (b) 3 (c)
4 (d) 5
2. The following code is not a BCD code. [ a]
a)Gray code
(b) Xs-3 code (c) 8421 code (d) All of these
3. A 15-bit hamming code requires [ a]
(a)4 parity
bits (b) 5 parity bits (c) 15 parity bits (d) 7 parity bits
4. The logic expression (A+B)(+) can be
implemented by giving the inputs A and B to a two-input [c ]
(a)NOR gate
(b) NAND gate (c) X-OR gate (d) X-NOR gate
5. Which of the following Boolean algebraic
expressions is incorrect? [ b]
(a)A+B=A+B (b)
A+AB=B (c) (A+B)(A+C)=A+BC (d) (A+)(A+B)=A
6. If=5,the
base(radix) of the number system is [b ]
a)5 (b) 6 (c)
7 (d) 8
7. The hexadecimal number system is used in
digital computers and digital systems to [d ]
(a) Perform
arithmetic operations (b) Perform logic operations
(c) Perform
arithmetic and logic operations (d) Input binary data into the system.
8. The logic expression A+B can be
implemented by giving inputs A and B to a two-input [ c]
(a)NOR gate
(b) NAND gate (c) X-OR gate (d) X-NOR gate
9. A gate is enabled when its enable input is
at logic 0. The gate is [a ]
(a)NOR (b) AND
(c) NAND (d) None of these
10. The output of a logic gate is 1 , when
all its inputs are at logic 0.The gate is either [a ]
(a)a NOR or an
X-NOR (b) a NAND or an X-OR
(c) an OR or
an X-NOR (d) an AND or an X-OR
11. In b’s complement method, the carry is Ignored and in(b-1)’s complement method the carry is add to the LSD
12. The MSB of
a binary number has a weight of 512,the number consists of 10 bits
13.Alpha numeric codes
are codes which represent letters of the alphabets and decimal numbers as a
sequence of 0s and 1s.
14. The interconnection of gates to perform a
variety of logical operations is called Logic
design
15. The NOR gate can function as a NOT gate
if All inputs connected togethor
16. The implicants which will definitely
occur in the final expression are called Essential prime
implicants
17. The prime implicant mode of a bunch of 0s
is called a False prime implicant
18.
Encoding is a process of converting familiar numbers or symbols into a coded
format.
19. A decoder with 64 output lines has Six select lines.
20. A decimal – to – BCD encoder is a 10 line to 4 line encoder.
Prepared by
Sowmya
&Srilatha