ELECTRONICS AND COMMUNICATION ENGINEERING IMPORTANT MCQ-MICROPROCESSORS

1. The minimum number of transistors required to implement a two input AND
gate is

A. 2
B. 4
C. 6
D. 8

Answer: C

2. Using DeMorgan’s Theorem we can convert any AND-OR structure into

A. NAND-NAND
B. OR-NAND
C. NAND-NOR
D. NOR-NAND

Answer: A

3. For a memory with a 16-bit address space, the addressability is
A. 16 bits
B. 8 bits
C. 2^16 bits
D. Cannot be determined

Answer: D

4. Because we wish to allow each ASCII code to occupy one location in
memory, most memories are _____ addressable.
A. BYTE
B. NIBBLE
C. WORD (16 bits)
D. DOUBLEWORD (32 bits)

Answer: A

5. Circuit A is a 1-bit adder; circuit B is a 1 bit multiplier.

A. Circuit A has more gates than circuit B
B. Circuit B has more gates than circuit A
C. Circuit A has the same number of gates as circuit B

(Hint: Construct the truth table for the adder and the multiplier)

Answer: A

6. When the write enable input is not asserted, the gated D latch ______ its
output.
A. can not change
B. clears
C. sets
D. complements

Answer: A

7. A structure that stores a number of bits taken “together as a unit” is a
A. gate
B. mux
C. decoder
D. register

Answer: D

8. We say that a set of gates is logically complete if we can build any
circuit without using any other kind of gates. Which of the following sets are
logically complete
A. set of {AND,OR}
B. set of {EXOR, NOT}
C. set of {AND,OR,NOT}
D. None of the above

Answer: C

9. Of the following circuits, the one which involves storage is
A. RS Latch
B. mux
C. nand
D. decoder

Answer: A

10. If the number of address bits in a memory is reduced by 2 and the
addressability is doubled, the size of the memory (i.e., the number of bits
stored in the memory)
A. doubles
B. remains unchanged
C. halves
D. increases by 2^(address bits)/addressability

Answer : C

12. If m is a power of 2, the number of select lines required for an m-input
mux is:

A. m
B. 2^m
C. log2 (m)
D. 2*m

Answer: C

13. For the number A[15:0] = 0110110010001111, A[14:13] is ______ A[3:2].

A. less than
B. greater than
C. the same as
d . cannot be determined

Answer: C

14. Which of the following conditions is not allowed in an RS latch?

A. R is asserted, S is asserted
B. R is asserted, S is negated
C. R is negated, S is asserted
D. R is negated, S is negated

Answer: A

15. Which of the following pair of gates can form a latch?
A. a pair of cross coupled OR
B. a pair of cross copled AND
C. a pair of cross coupled NAND
D. a cross coupled NAND/OR

Answer: C

16. ‘Burst refresh’ in DRAM is also called

A. Concentrated refresh
B. Distributed refresh
C. Hidden refresh
D. None of the above

Answer: A

17. The number of interrupt lines in 8085 is

A. 2
B. 3
C. 4
D. 5

Answer: D

18. A real number consists of

A. integer part
B. integer part and fraction part
C. integer part, fraction part along with positive or negative sign
D. none of the above

Answer: C

19. Assertion (A): Negative values of incremental operator in DO loop are
allowed in Fortran 77 but not in earlier versions of Fortran.

Reason (R): Fortran 77 has better array facilities than earlier versions of
Fortran.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct R is wrong
D. A is wrong R is correct

Answer: B

20. Which of the following is not treated as hexadecimal constant by
assembler in 8085?

A. 45 H
B. 6 AFH
C. 234
D. 64 H

Answer: C

21. IC 7485 cannot be cascadeD.

A. True
B. False

Answer: B

22. An I/O processor controls the flow of information between

A. cache memory and I/O devices
B. main memory and I/O devices
C. two I/O devices
D. cache and main memory

Answer: B

23. MS Access is a DBMS software.

A. True B. False

Answer: A

24. When .9432 E – 4 is subtracted from .5452 E – 3 in normalized floating
point mode

A. none of the numbers is changed
B. .9432 E – 4 is changed to .09432 E – 3 and .5452 E – 3 is not changed
C. .5452 E – 3 is changed to 5.452 E – 4 but .9432 E – 4 is not changed
D. both Ihe numbers are changed and their exponents are, made equal to -5

Answer: B

25. DS directive in 8085

A. forces the assembler to reserve one byte of memory
B. forces the assembler to reserve a specified number of bytes in the memory
C. forces the assembler to reserve a specified number of consecutive bytes in
the memory
D. none of the above

Answer: C

26. Which of the following is a valid integer constant?

A. 127
B. 127.0
C. 127
D. 125 + 3

Answer: A

27. The five flags in 8085 are designated as

A. Z, CY, S, P and AC
B. D, Z, S, P, AC
C. Z, C, S, P, AC
D. Z, CY, S, D, AC

Answer: A

28. In 8085 which addressing mode is also called inherent addressing?

A. Direct
B. Register
C. Implicit
D. Immediate

Answer: C

29. It is possible to copy a file in the same directory.

A. True
B. False

Answer: A

30. In a computer the data transfer between hard disk and CPU is nearly the
same as that between diskette and CPU.

A. True
B. False

Answer: B

31. The timing difference between a slow memory and fast processor can be
resolved if

A. processor is capable of waiting
B. external buffer is used
C. either (a) or (b)
D. neither (a) nor (b)

Answer: C

32. In 8086 the number of bytes which can be addressed directly is about

A. 1000
B. 10000
C. 100000
D. one million

Answer: D

33. In Fortran 77 a variable name can contain special characters.

A. True
B. False

Answer: B

34. Which of the following is not a general purpose peripheral?

A. I/O port
B. Programmable interrupt controller
C. Programmable CRT controller
D. Programmable interval timer

Answer: C

35. Each instruction in assembly language program has the following fields:

Lable field
Mnemonic field
Operand field
Comment field
The correct sequence of these fields is?
A. 1, 2, 3, 4
B. 1, 2, 4, 3
C. 2, 1, 3, 4
D. 2, 1, 4, 3

Answer: A

36. In one’s complement 8 bit representation 11111111 represents

A. +0
B. -0
C. +1
D. -1

Answer: B

37. The operating modes of 8255 A are called

A. mode 0 and mode 1
B. mode 0, mode 1 and mode 2
C. mode 0 and mode 2
D. mode 0, mode 2 and mode 3

Answer: B

38. Which of the following is type declaration statement in C?

A. int bar
B. s = s + 1
C. king = horse + 1
D. prin = prin * prin

Answer: A

39. Internet is a worldwide network of computers where most of the
information is freely available.

A. True
B. False

Answer: A

40. A 37 bit mantissa has an accuracy of

A. 6 decimal places
B. 8 decimal places
C. 10 decimal places
D. 11 decimal places

Answer: D

41. In a C expression using assignment operators, relational operators and
arithmetic operators, the hierarchy of operations (in the absence of
parenthesis) is

A. assignment, relational, arithmetic
B. relational, assignment, arithmetic
C. arithmetic, assignment, relational
D. arithmetic, relational, assignment

Answer: D

42. In 8085, the pins for SID and SOD are

A. 4 and 5 respectively
B. 5 and 4 respectively
C. 3 and 4 respectively
D. 4 and 3 respectively

Answer: B

43. Assertion (A): Each memory chip has its own address latch.

Reason (R): ALE signal comes out of microprocessor 8085 and goes to memory
chip.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct R is wrong
D. A is wrong R is correct

Answer: D

44. An e-mail message can be sent to many recipients.

A. True
B. False

Answer: A

45. In C the keywords are also called

A. special words
B. reserved words
C. class words
D. character words

Answer: B

46. The character set of Fortran 77 includes lower case alphabets a to z.

A. True
B. False

Answer: B

47. Which memory has read operation, byte erase, byte write and chip erase?

A. RAM
B. UVEPROM
C. EEPROM
D. both (b) and (c)

Answer: C

48. The forms of IF statements in FORTRAN 77 are called

A. logical IF and Block IF
B. logical IF, block IF and arithmetic IF
C. logic IF, block IF, arithmetic IF and negate IF
D. logical IF and arithmetic IF

Answer: B

49. In 8085

A. P flag is set when the result has even parity
B. P flag is set when the result has odd parity
C. P flag is reset when the result has odd parity
D. P flag is reset when the result has even parity

Answer: A

50. If the sign bit of mantissa is 0 and the exponent is increased from a
positive to a more negative number the result is

A. a larger floating point number
B. a smaller floating point number
C. either (a) or (b) depending on the actual number
D. a negative floating point number

Answer: A
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