### Computer Science - Digital Computer Electronics MCQs Part 1

1. Conversion of decimal number 6110 to it's binary number equivalent is

A.
1100112
B.
110011102
C.
1111012
D.
111112
E.
None of the above

2. An OR gate can be imagined as

A.
switches connected in series
B.
switches connected in parallel
C.
MOS transistors connected in series
D.
All of the above
E.
None of the above

3. Address 200H contains the byte 3FH. What is the decimal equivalent of 3FH

A.
63
B.
32
C.
16
D.
38
E.
None of the above

4. Conversion of an octal number 1128 to hexadecimal number is

A.
4A16
B.
5A16
C.
1516
D.
2016
E.
None of the above

5. The functional difference between SR flip-flop and JK flip-flop is that

A.
JK flip-flop is faster than SR flip-flop
B.
JK flip-flop has a feed back path
C.
JK flip-flop accepts both inputs 1
D.
JK flip-flop does not require external clock
E.
None of the above

6. The inverter OR gate and AND gate are called decision-making elements because they can recognize some input _____ while disregarding others. A gate recognizes a word when its output is _____

A. words, high
B. bytes, low
C. bytes, high
D. character, low
E. None of the above

7. A positive AND gate is also a negative

A. NAND gate
B. NOR gate
C. AND gate
D. OR gate
E. None of the above

8. In which code the successive code characters differ in only one bit position?

A. gray code
B. excess 3 code
C. 8421 code
D. algebraic code
E. None of the above

9. Conversion of binary number 1011012 to hexadecimal is

A. 3716
B. 2D16
C. 2E16
D. 2716
E. None of the above

10. ASCII and EBCDIC differ in

A. their efficiency in storing data
B. the random and sequential access method
C. the number of bytes used to store characters
D. their collecting sequences
E. None of the above

11. A p- channel enhancement type MOSFET performs much the same function as a PNP transistor, except that

A. it operates much faster
B. it is considerably larger
C. it is controlled by voltage rather than by current, so that it requires very little current at the control terminal
D. it is controlled by current rather than by voltage like a bipolar transistor.
E. None of the above

12. De Morgan's second therm says that NAND gate is equivalent to a bubbled _____ gate.

A. AND
B. XAND
C. XOR
D. OR
E. None of the above

13. What logic function is produced by adding an inverter to each input and the output of an AND gate?

A. NAND
B. NOR
C. OR
D. XOR
E. None of the above

14. When a transistor is cut off or saturated, transistor _____ have almost no effect

A. wave
B. variations
C. stage
D. circuits
E. None of the above

15. Express -7 as 16-bit signed binary numbers.

A. 0000 0000 0000 0111
B. 1000 0000 0000 0111
C. . 0111 0000 0000 0001
D. 0111 0000 0000 0000
E. None of the above

16. With an RS latch a high S and low R sets the output to _____ ; a low S and a high R _____ the output to low.

A. No change, set
B. Race, high
C. high, reset
D. set, reset
E. None of the above

17. Flip-flop outputs are always

A. complimentary
B. the same
C. independent of each other
D. same as inputs
E. None of the above

18. The output 0 and 1 levels for TTL logic family is approximately

A. 0.1 and 5 V
B. 0.6 and 3.5 V
C. 0.9 and 1.75V
D. -1.75 and -0.9 V
E. None of the above

19. A _____ TTL device can sink up to 16mA and can source up to 400 MA.

A. Low-power
B. high-power
C. Standard
D. Schottky
E. None of the above

20. What is the 2's complement of 0011 0101 1001 1100 number?

A. 1100 1010 1100 1011
B. 1100 1010 0110 0011
C. 1100 1010 0110 0100
D. 1100 1010 1111 1111
E. None of the above

21. Digital design often starts by constructing a _____ table.

A. Standard
B. Two-stage
C. Truth
D. Two-dinensional
E. None of the above

22. The hexadecimal digits are 0 to 9 and A to _____

A. E
B. F
C. G
D. D
E. None of the above

23. The ASCII

A. is a subset of 8-bit EBCDIC
B. is used only in Western Countries
C. is version II of the ASC Standard
D. has 128 characters, including 32 control characters
E. None of the above

24. An OR gate has 6 inputs. What is the only input word that produces a 0 output?

A. 000000
B. 000111
C. 111000
D. 111111
E. None of the above

25. A diagram that illustrates the ore (Logic) of functions in a progran called a

A. Flowchart
B. Sequence of steps
C. Direction of flow
D. All of the above
E. None of the above

26. The Gray code for decimal 7 is

A. 0111
B. 1011
C. 0100
D. 0101
E. None of the above

27. The time required for a pulse to decrease from 90 to 10 percent of its maximum value is known as

A. rise time
B. decay time
C. binary level transition period
D. propagation delay
E. None of the above

28. Conversion of binary number 1010000101112 to hexadecimal number is

A. D8F916
B. A8B916
C. A1716
D. D9F816
E. None of the above

29. _____dominates the LSI field, and _____ is used extensively where lowest power consumption is necessary.

A. NMOS, PMOS
B. PMOS, CMOS
C. NMOS, CMOS
D. MOSFET, PMOS
E. None of the above

30. Conversion of an octal number 1438 to its decimal number is

A. 9010
B. 97110
C. 9910
D. 10710
E. None of the above

31. How many inputs signals can a gate have?

A. one
B. more than one
C. two only
D. both (a) and (b)
E. None of the above

32. A combinational logic circuit which is used when it is desired to send data from two or more source through a single transmission line is known as

A. encoder
B. decoder
C. multiplexer
D. demultiplexer
E. None of the above

33. Conversion of binary number 10010012 to hexadecimal is

A. 4016
B. 3916
C. 4916
D. 4216
E. None of the above

34. Which logic family dissipates the minimum power?

A. DTL
B. TTL
C. ECL
D. CMOS
E. None of the above

35. What logic function is obtained by adding an inverter to the inputs of an AND gate?

A. OR
B. NAND
C. XOR
D. NOR
E. None of the above

36. A bus is a group of _____ carrying digital signals.

A. wires
B. gates
C. transistors
D. registers
E. None of the above

37. The simplified form of the Boolean expression (X + Y + XY)(X + Z) is

A. X + Y + Z
B. XY + YZ
C. X + YZ
D. XZ + Y
E. None of the above

38. De Morgan's first theorem says that a NOR gate is equivalent to a bubbled _____ gate.

A. AND
B. XAND
C. XOR
D. NOR
E. None of the above

39. Addition of 102 and 112 is

A. 1002
B. 1012
C. 1112
D. 1102
E. None of the above

40. How many bits are required to encode all twenty six letters ten symbols, and ten numerals?

A. 5
B. 6
C. 2
D. 3
E. None of the above

41. An inverter is also called a _____ gate.

A. NOT
B. OR
C. AND
D. NAND
E. None of the above

42. Conversion of decimal number 1310 to it's octal number equivalent is

A. 158
B. 178
C. 138
D. 118
E. None of the above

43. The binary number 1100 0101 has _____ bytes

A. 1
B. 2
C. 4
D. 8
E. None of the above

44. With a NAND latch a low R and a low S produce a _____ condition.

A. race
B. set
C. reset
D. no change
E. None of the above

45. Which of the following logic families has the highest noise immunity?

A. RTL
B. DTL
C. TTL
D. HTL
E. None of the above

46. The ALU carries out arithmetic and logic operations. It processes _____ numbers rather than decimal numbers.

A. decimal
C. binary
D. All of the above
E. None of the above

47. Conversion of decimal number 7110 to it's binary number equivalent is

A. 1100112
B. 11100112
C. 01100112
D. 10001112
E. None of the above

48. Which of the following flip-flops is free from race around problem?

A. T flip-flop
B. SR flip-flop
C. master slave JK flip-flop
D. All of the above
E. None of the above

49. Conversion of decimal number 6710 to it's octal number equivalent is

A. 1008
B. 1038
C. 1098
D. 998
E. None of the above

50. A NOR gate has two or more input signals. All input must be _____ to get a high output

A. low
B. high
C. some low some high
D. 1's
E. None of the above