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Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
DIPLOMA ENGINEERING- C to D Bridge Course Examination WINTER 2018
Subject Code: C322402 Date: 09-01-2019
Subject Name: Digital Electronics
Time: 10:30 AM TO 12:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Each question is of 1 mark.
4. Use of only simple calculator is permitted. (Scientific/Higher Version not allowed).
5. English version is authentic
No.
Question Text and Option.
1.
Which number system has a base of 16
A.
Decimal
B.
Hexadecimal
C.
Octal
D.
binary

16
A.

B.

C.

D.

2.
In 1-to-4 demultiplexer, how many select lines are required?
A.
2
B.
3
C.
4
D.
5

4
A.
2
B.
3
C.
4
D.
5
3.
In a multiplexer the output depends on its
A.
Data inputs
B.
Select inputs
C.
Select outputs
D.
None of the Mentioned

.....
A.

B.

C.

D.

4.
The largest two digit hexadecimal number is
A.
(FE)16
B.
(FD)16
C.
(FF)16
D.
(EF)16

.....
A.
(FE)16
B.
(FD)16
C.
(FF)16
D.
(EF)16
5.
The quantity of double word is
A.
16 bits
B.
32 bits
C.
64 bits
D.
8 bits


A.
16 bits
B.
32 bits
C.
64 bits
D.
8 bits
6.
(170)10 is equivalent to
A.
(FD)16
B.
(DF)16
C.
(AA)16
D.
(AF)16

(170)10
A.
(FD)16
B.
(DF)16
C.
(AA)16
D.
(AF)16
7.
Convert (214)8 into decimal:
2/9
A.
(140)10
B.
(144)10
C.
(141)10
D.
(143)10

(214)8
A.
(140)10
B.
(144)10
C.
(141)10
D.
(143)10
8.
Convert the hexadecimal number (1E2)16 to decimal:
A.
482
B.
485
C.
483
D.
486

number (1E2)16
A.
482
B.
485
C.
483
D.
486
9.
The octal equivalent of the decimal number (417)10 is
A.
(641)8
B.
(619)8
C.
(640)8
D.
(658)8

(417)10
A.
(641)8
B.
(619)8
C.
(640)8
D.
(658)8
10.
Convert binary to octal: (110110001010)2 =…………
A.
(6612)8
B.
(6615)8
C.
(6614)8
D.
(6619)8

(110110001010)2 =…………
A.
(6612)8
B.
(6615)8
C.
(6614)8
D.
(6619)8
11.
complement of 11001011 is
A.
00110101
B.
00110111
C.
00110100
D.
00111111

11001011
A.
00110101
B.
00110111
C.
00110100
D.
00111111
12.
The decimal number 10 is represented in its BCD form as
A.
1010
B.
01010
C.
00010000
D.
001010

10 ....
A.
1010
B.
01010
C.
00010000
D.
001010
13.
Add the two BCD numbers: 1001 0100
A.
00110011
B.
1101
C.
00001101
D.
1101101

BCD 1001
A.
00110011
B.
1101
C.
00001101
D.
1101101
14.
According to boolean law: A 1
A.
1
B.
A
C.
A1
D.
1A

A 1
A.
1
B.
A
C.
A1
D.
1A
15.
A(A
A.
A
B.
B
C.
AB)
D.
1

A(A
A.
A
B.
B
C.
AB)
D.
1
3/9
16.
DeMorgan's theorem states that
A.

B.
B
C.

D.
None of the Mentioned

.........
A.

B.
B
C.

D.
None of the Mentioned
17.
The NOR gate output will be high if the two inputs are
A.
00
B.
01
C.
11
D.
10

NOR .......
A.
00
B.
01
C.
11
D.
10
18.
Which is typically the longest?
A.
bit
B.
Word
C.
nibble
D.
Byte


A.

B.

C.

D.

19.
Convert hexadecimal value C1 to binary.
A.
11000001
B.
111000100
C.
1000111
D.
111000001


A.
11000001
B.
111000100
C.
1000111
D.
111000001
20.
The sum of 11101 10111 equals
A.
100100
B.
110100
C.
100001
D.
110011

11101 10111 .....
A.
100100
B.
110100
C.
100001
D.
110011
21.
How many bits are in an ASCII character?
A.
16
B.
8
C.
7
D.
4

ASCII ...........
A.
16
B.
8
C.
7
D.
4
22.
The binary number 1110 is equal to the decimal number
A.
3
B.
1
C.
7
D.
14

1110= ........
A.
3
B.
1
C.
7
D.
14
23.
The difference of 111 001 equals
A.
100
B.
111
C.
001
D.
110
111 001 ..................
4/9

A.
100
B.
111
C.
001
D.
110
24.
Convert the binary number 1100 to Gray code
A.
0011
B.
1010
C.
1100
D.
1001

1100
A.
0011
B.
1010
C.
1100
D.
1001
25.
Which of the following is an invalid BCD code
A.
0011
B.
1101
C.
0101
D.
1001

BCD
A.
0011
B.
1101
C.
0101
D.
1001
26.
What decimal number does 25 represent
A.
10
B.
31
C.
25
D.
32

25 ..............
A.
10
B.
31
C.
25
D.
32
27.
Convert the Gray code 1011 to binary
A.
1011
B.
1010
C.
0100
D.
1101

1011
A.
1011
B.
1010
C.
0100
D.
1101
28.
Determine the decimal equivalent of the signed binary number 11110100 in complement.
A.
116
B.
-12
C.
11
D.
128

11110100 ......
A.
116
B.
-12
C.
11
D.
128
29.
Digital electronics is based on the numbering system
A.
decimal
B.
binary
C.
octal
D.
hexadecimal

........
A.

B.

C.

D.

30.
The complement of 10011101 is
A.
01100010
B.
10011110
C.
01100001
D.
01100011

10011101 ........
A.
01100010
B.
10011110
C.
01100001
D.
01100011
31.
3 × 101 7 × 100 is equal to
A.
3.7
B.
37
C.
10
D.
317

3 × 101 7 × 100=…….
A.
3.7
B.
37
C.
10
D.
317
32.
The decimal number 18 is equal to the binary number
A.
11110
B.
10001
5/9
C.
10010
D.
1111000

....
A.
11110
B.
10001
C.
10010
D.
1111000
33.
The complement of 11100111 is
A.
11100110
B.
00011001
C.
00011000
D.
00011010

11100111
A.
11100110
B.
00011001
C.
00011000
D.
00011010
34.
The output of an AND gate with three inputs, and is HIGH when
A.
A B C 0
B.
A B C 0
C.
A B C
D.
A B C 1

AND C ............ 1
A.
A B C 0
B.
A B C 0
C.
A B C
D.
A B C 1
35.
The output of an OR gate with three inputs, and is LOW when
A.
A B C 0
B.
A B C 1
C.
A B C 1
D.
all of the above

OR C ............ 0
A.
A B C 0
B.
A B C 1
C.
A B C 1
D.

36.
Which of the following logical operations is represented by the sign in Boolean algebra?
A.
inversion
B.
AND
C.
OR
D.
complementation


A.

B.
AND
C.
OR
D.

37.
Output will be a LOW for any case when one or more inputs are zero for
A.
OR gate
B.
NOT gate
C.
AND gate
D.
NOR gate

........
A.
OR gate
B.
NOT gate
C.
AND gate
D.
NOR gate
38.
TTL operates from a
A.
9-volt supply
B.
3-volt supply
C.
12-volt supply
D.
5-volt supply

TTL ........
A.
9-volt supply
B.
3-volt supply
C.
12-volt supply
D.
5-volt supply
39.
The Boolean expression for a 3-input AND gate is
A.
X AB
B.
X ABC
C.
X A B C
D.
X AB C

.....
A.
X AB
B.
X ABC
C.
X A B C
D.
X AB C
40.
CMOS IC operating from a 3-volt supply will consume
A.
less power than a TTL IC
B.
more power than a TTL IC
C.
the same power as a TTL IC
D.
no power at all

3 CMOS IC ............
6/9
A.
TTL IC
B.
TTL IC
C.
TTL IC
D.
.
41.
The output of a NOT gate is HIGH when
A.
the input is LOW
B.
the input is HIGH
C.
power is applied to the gate's IC
D.
power is removed from the gate's IC

NOT
A.

B.

C.
IC
D.
IC
42.
If the input to a NOT gate is A and the output is then
A.
X A
B.
C.
X 0
D.
none of the above

NOT A X ...........
A.
X A
B.
C.
X 0
D.
none of the above
43.
The output of an exclusive-OR gate is HIGH if
A.
all inputs are LOW
B.
all inputs are HIGH
C.
the inputs are unequal
D.
none of the above

exclusive-OR ...................
A.

B.

C.

D.

44.
The logic expression for a NOR gate is
A.
B.
C.
D.

NOR
A.
B.
C.
D.
45.
How many AND gates are found in a 7411 IC
A.
1
B.
2
C.
3
D.
4

7411 IC AND
A.
1
B.
2
C.
3
D.
4
46.
The basic types of programmable arrays are made up of
A.
AND gates
B.
OR gates
C.
NAND and NOR gates
D.
AND gates and OR gates

........
A.
AND gates
B.
OR gates
C.
NAND and NOR gates
D.
AND gates and OR gates
47.
Which of the following is not a basic Boolean operation?
A.
OR
B.
NOT
C.
AND
D.
FOR


A.
OR
B.
NOT
C.
AND
D.
FOR
48.
Which of the following gates is described by the expression
A.
OR
B.
NOT
C.
AND
D.
NAND


A.
OR
B.
NOT
C.
AND
D.
NAND
49.
What is the Boolean expression for a four-input OR gate?
7/9
A.
Y A B C D
B.
Y AB C D
C.
A B C D
D.
A B C D

OR ......
A.
Y A B C D
B.
Y AB C D
C.
A B C D
D.
A B C D
50.
The output of a NAND gate is LOW if
A.
all inputs are LOW
B.
all inputs are HIGH
C.
any input is LOW
D.
any input is HIGH

NAND LOW .........
A.
LOW
B.
HIGH
C.
LOW
D.
HIGH
51.
Which of the following expressions is in the sum-of-products form?
A.

B.

C.
AB(CD)
D.
AB CD


A.

B.

C.
AB(CD)
D.
AB CD
52.
Converting the Boolean expression LM M(NO PQ) to SOP form, we get
A.
LM MNOPQ
B.
L MNO MPQ
C.
LM M NO MPQ
D.
LM MNO MPQ

LM M(NO PQ SOP .......
A.
LM MNOPQ
B.
L MNO MPQ
C.
LM M NO MPQ
D.
LM MNO MPQ
53.
A Karnaugh map is a systematic way of reducing which type of expression?
A.
product-of- products
B.
exclusive NOR
C.
sum-of-products
D.
exclusive OR


A.

B.

C.

D.

54.
Which of the examples below expresses the commutative law of multiplication?
A.
A B B A
B.
AB B A
C.
AB BA
D.
AB A × B


A.
A B B A
B.
AB B A
C.
AB BA
D.
AB A × B
55.
Identify the type of gate below from the equation
A.
Ex-NOR gate
B.
OR gate
C.
Ex-OR gate
D.
NAND gate


A.
Ex-NOR gate
B.
OR gate
C.
Ex-OR gate
D.
NAND gate
56.
Which type of gate can be used to add two bits?
A.
Ex-OR
B.
Ex-NOR
C.
Ex-NAND
D.
NOR


A.
Ex-OR
B.
Ex-NOR
C.
Ex-NAND
D.
NOR
57.
The Ex-NOR is sometimes called the
A.
parity gate
B.
equality gate
C.
inverted OR
D.
parity gate or the equality gate

Ex-NOR .......
8/9
A.

B.

C.

D.

58.
Which of the examples below expresses the distributive law?
A.
C A
B.
A(B AB AC
C.
A AB AC
D.
C


A.
C A
B.
A(B AB AC
C.
A AB AC
D.
C
59.
Which of the examples below expresses the associative law of addition:
A.
A C
B.
A A
C.
C
D.
ABC A B C


A.
A C
B.
A A
C.
C
D.
ABC A B C
60.
A NOR gate with one HIGH input and one LOW input:
A.
will output a HIGH
B.
functions as an AND
C.
will not function
D.
will output a LOW

NOR ......
A.

B.
AND
C.

D.

61.
An OR gate with inverted inputs functions as
A.
an AND gate.
B.
a NAND gate.
C.
a NOR gate.
D.
an inverter.

OR .......
A.
an AND gate.
B.
a NAND gate.
C.
a NOR gate.
D.
an inverter.
62.
How many 3-line-to-8-line decoders are required for a 1-of-32 decoder?
A.
1
B.
2
C.
4
D.
8


A.
1
B.
2
C.
4
D.
8
63.
How many 1-of-16 decoders are required for decoding a 7-bit binary number?
A.
5
B.
6
C.
7
D.
8


A.
5
B.
6
C.
7
D.
8
64.
Which gate is best used as a basic comparator?
A.
NOR
B.
OR
C.
Exclusive-OR
D.
AND


A.
NOR
B.
OR
C.
Exclusive-OR
D.
AND
65.
When adding an even parity bit to the code 110010, the result is
A.
1110010
B.
1111001
C.
110010
D.
001101

110010 ..............
A.
1110010
B.
1111001
C.
110010
D.
001101
66.
How is a J-K flip-flop made to toggle?
A.
J K 0
B.
J K 0
C.
J K 1
D.
J K 1
9/9


A.
J K 0
B.
J K 0
C.
J K 1
D.
J K 1
67.
How many flip-flops are in the 7475 IC?
A.
1
B.
2
C.
4
D.
8

7475 IC
A.
1
B.
2
C.
4
D.
8
68.
A J-K flip-flop is in a "no change" condition when
A.
J K 1
B.
J K 0
C.
J K 1
D.
J K 0

"
A.
J K 1
B.
J K 0
C.
J K 1
D.
J K 0
69.
How many flip-flops are required to make a MOD-32 binary counter
A.
3
B.
45
C.
5
D.
6

MOD-32
A.
3
B.
45
C.
5
D.
6
70.
A flip-flop has
A.
one stable state
B.
three stable state
C.
Two stable state
D.
none of the above

ને...............
A.

B.

C.

D.