Multiple Choice Questions and Answers on Microprocessors

Multiple Choice Questions and Answers on Microprocessors

Q1. 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
Q2. 8255 A is a
a) programmable peripheral interface
b) I/O device
c) memory chip
d) none of the above
Answer : a
Q3. When the mains supply is switched off the contents of primary computer memory are lost.
a) True
b) False
Answer : a
Q4. Incompatibility between memory and I/O device may be due to
a) timing according to which data transfer is to take place
b) electrical characteristics of the two devices
c) format of data transfer
d) all of the above
Answer : d
Q5. If 8085 is required to add two 32 bit numbers, the numbers of addition sequences is
a) 1
b) 2
c) 4
d) 8
Answer : c
Q6. The number of computer viruses is some thousands
a) True
b) False
Answer : a
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Q7. Assertion (A): C has a large number of library functions classified as arithmetic functions, data conversion functions, character classified functions, string manipulation functions, searching and sorting functions etc.

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Reason (R): 8086 uses a segment : offset addressing scheme.

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
Q8. The box on the external left of the title bar of menu is called control menu box.
a) True
b) False
Answer : a
Q9.The maximum number of characters for variable names in C is
a) 4
b) 8
c) 12
d) 16
Answer : b
Q10. An 8 bit wide 4 word sequential memory has
a) Eight 4 bit shift registers
b) Eight 8 bit shift registers
c) Four 8 bit shift registers
d) Four 4 bit shift registers
Answer : a
Q11. Which of the following statements is non-executable in FORTRAN 77?
a) DO
b) ASSIGN
c) END
d) DIMENSION
Answer : d
Q12. In C the range of real constants expressed in exponential form is
a) -2.3 e 37 to + 2.3 e 37
b)-3.4 e 38 to + 3.4 e 38
c) -3.4 e 37 to + 3.4 e 37
d) -2.3 e 38 to + 2.3 e 38
Answer : c

Q13. Assertion (A): The ‘do while’ statement is used less frequently than the ‘while’ statement.

Reason (R): For most applications it is more natural to test for continuation of loop at the beginning than at the end of loop.

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 : a
Q14. Consider the following in Cint k

float a ;
k = 4.2
a = 300

The values stored in computer memory for k and a are respectively

a)4.2 and 300
b) 4 and 300 respectively
c)4.2 and 300.00 respectively
d)4 and 300.00 respectively
Answer : d
Q15. The statement IMPLICIT INTEGER (A - F) in FORTRAN identifies
a) all variable names which begin with A, B, C, D, E or F as being of integer type
b) all character names which begin with A, B, C, D, E, or F as being of integer type
c) all variable names which begin with A and have 6 characters
d) none of the above
Answer : a
Q16. MS Excel is an application software for financial planning.
a) True
b) False
Answer : a

Q17. Assertion (A): C has 32 keywords like auto, if, do, float etc.

Reason (R): Key words can not be used as variable names in C.

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

Q18. Consider the following statements

  1. A total of about 1 million bytes can be directly accessed by 8086 microprocessor.
  2. The 8086 has thirteen 16 bit registers.
  3. The 8086 has eight flags.
  4. Compared to 8086, the 80286 provides a higher degree of memory protection.

Of the above statements

a) 1, 2, 3, 4 are correct
b) 1, 3, 4 are correct
c) 1, 2, 4 are correct
d) 1, 2, 3 are correct
Answer : c

Q19. Consider the following program for 8085

MVIA, 00H
MVIA, 53H
CMA

The contents of accumulator at the end of this program will be

a) OACH
b)  53 H
c) OADH
d) 54 H
Answer : a
Q20. In Pascal the repeat and while loops will terminate
a) only when the logical expression controlling the loop becomes true for both repeat and while loops
b) only when the logical expression controlling the loop becomes false for both repeat and while loops
c) only when the logical expression controlling the loop becomes true for repeat loop and false for while loop
d) only when the logical expression controlling the loop becomes false for repeat loop and true for while loop
Answer : c
Q21. Which of the following can be accessed only sequentially?
a) Floppy disk
b) Hard disk
c) Magnetic tape
d) ROM
Answer : c
Q22. MICR stands for
a) Magnetic Ink Chart Receipt
b) Magnetic Ink Character Recognition
c) Magnetic Ink Chart Recognition
d) Magnetic Ink Character Receipt
Answer : b
Q23.  8085 has 6 sign flags?
a) True
b) False
Answer : b
Q24. JCOKE = 3
JCOKE = JCOKE + 1
GO TO (5, 8, 9, 11, 15, 16 18, 20) JCOKE.
After the execution of above statement, the control is transferred to statement number
a) 8
b) 11
c) 16
d) 20
Answer : b
Q25. Binary number 1101.101 is equivalent to decimal number?
a) 13.5
b) 13.75
c) 13.625
d) 13.875
Answer : c
Q26. Expression ++i is equivalent to
a) i = i + 2
b) i = i + 1
c) i = i – 1
d) ii +i +i
Answer : b
Q27. To multiply a number by 8 in 8085 we have to use RAL instruction
a) once
b) twice
c) thrice
d) four times
Answer : c
Q28. IC (instruction cycle), FC (fetch cycle) and EC (executive cycle) are related as
a) IC = FC – EC
b) IC = FC + EC
c) IC = FC + 2EC
d) EC = IC + EC
Answer : b
Q29. Which of the following is not a valid variable name in C?
a) 1 a
b) a 1 2
c) a b 123
d) a b c123
Answer : a
Q30. Which of the following is not an integer constant?
a) 0
b) -8
c) +1074
d) -8.1
Answer : d

Q31. Let JCOKE = 98 and LPEPSI = 42 Consider the statement

IF (JCOKE – 3 * LPEPSI) 5, 6, 7
5 JCOKE = JCOKE + 5
6 JCOKE = JCOKE + 8
7 JCOKE = JCOKE + 11

The value of JCOKE after the execution of above statement will be

a) 103
b) 106
c) 109
d) none of the above
Answer : a
Q32. Which of the following is not a valid integer constant in C (for 16 bit)?
a) 321
b) -162
c) -65321
d) +1
Answer : c
Q33. If A = 20 and B = – 7 in PASCAL, A mod B =
a) 6
b) 2
c) -1
d) 3
Answer : a
Q34. Which of the following is a computer language?
a) MS WORD
b) Page maker
c) MS EXCEL
d) LISP
Answer : d
Q35. Read the following statements about files in Pascal
  1. A file is a data structure which consists of a sequence of components of the same type.
  2. The number of components in a file is variable.
  3. The components in a file can be accessed only sequentially starting from the beginning of the file.

Which of the above are correct?

a) All
b) 1 and 2 only
c) 2 and 3 only
d) 1 and 3 only
Answer : a
Q36. In ALU 1C 74181 the addition and subtraction is in
a)  2’s complement
b) 1’s complement
c) binary
d) none of the above
Answer : a
Q37. EEPROM permits
a) read operation only
b) read and byte erase operations
c) read, byte erase and byte write operations
d) read, byte erase, byte write and chip erase operations
Answer : d
Q38. Which of the following is invalid in Basic?
a) A ** B + – C
b) A ** B – C
c) A * B – C
d) A * B – C ** D
Answer : a
Q39. An advantage of memory interlacing is that
a) a larger memory is obtained
b) effective speed of memory is increased
c) cost of memory is reduced
d) a non-volatile memory is obtained
Answer : b
Q40. The number of operator to accomplish basic arithmetic in Java is
a) 4
b) 5
c) 6
d) 7
Answer : b
Q41. The signals in 8086 are classified into
a)  minimum mode and maximum mode
b) decrement mode and increment mode
c) low mode and high mode
d) none of the above
Answer : a
Q42. Which of the following instructions have only one operand?
a) Multiply
b) Add
c)Shift
d) Subtract
Answer : c
Q43. ‘Rotate instruction’ in microprocessor belongs to
a) data transfer group
b) arithmetic group
c) logic group
d) branch group
Answer : c
Q44. In which of the following instructions of 8085 are the contents of accumulator complemented?
a)  STC
b) CMC
c) CMA
d) RAL
Answer : c

Q45. Assertion (A): Microprocessors 8086 and 8088 are very similar in organisation and have identical instruction sets.

Reason (R): If clock speed is same the execution time of 8088 and 8086 are exactly equal.

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 : c
Q46. In which of the following logical group instructions of 8085 is the addressing mode ‘immediate’?
a) ANA r
b) ANA M
c) ANI data
d) XRA r
Answer : c
Q47. The word size accessible at a time from the memory subsystem depends on
a) width of data bus
b) width of address bus
c) width of control bus
d) both (b) and (c)
Answer : a
Q48. Microprocessor 8088 has
a) 16 bit registers and 16 bit data bus
b) 8 bit registers and 8 bit data bus
c) 8 bit registers and 16 bit data bus
d) 16 bit registers and 8 bit data bus
Answer : d

Q49. Assertion (A): In 8085, P flag is for parity checking.

Reason (R): If the result of ALU has even parity, P flag is set and if the result has odd parity, P flag is reset.

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 : a
Q50. Which of the following is not a special purpose peripheral?
a) Programmable DMA controller
b) Programmable Floppy disc controller
c) Programmable Hard disc controller
d) Programmable CRT controller
Answer : a
Q51. Which of the following is not an interrupt line in 8085?
a) TRAP
b) RST 5.5
c) RST 7.5
d) RST 9.5
Answer : d
Q52. In 8085, F register has 8 bits.
a) True
b) False
Answer : a
Q53. The general purpose register code for accumulator in 8085 is
a) 111
b) 000
c) 001
d) 1111
Answer : a
Q54. Which of the following is not an internal DOS command?
a) VER
b) COPY
c) MEM
d) DATE
Answer : c
Q55. In 8085, high level on INTR line can be recognised only if
a) TRAP and RST lines are high
b) TRAP and RST lines are not high
c) TRAP line is high but not RST line
d) RST line is high but not TRAP line
Answer : b
Q56. Which 8085 instruction causes exchange of contents of stack pointer with the contents of H L register pair?
a) XTHL
b) PCHL
c) LHLD
d) MVIA
Answer : a
Q57. A microprocessor needs memory chips and input-output chip to form a microcomputer.
a) True
b) False
Answer : a
Q58. Windows automatically starts CD player when one inserts audio CD in CD-ROM drive.
a) True
b) False
Answer : a
Q59.In 8086 the word address is
a) the address of the least significant byte
b) the address of most significant byte
c) either (a) or (b) depending on the word
d) neither (a) nor (b)
Answer : a
Q60. The instruction MOV r1r2 in 8085
a) causes contents of registers r2 to be moved to r, and uses register addressing
b) causes contents of registers r1 to be moved to r2 and uses register addressing
c) causes contents of registers r1 to be moved to r2 and uses register immediate addressing
d) causes contents of registers r2 to be moved to r1 and uses register immediate addressing
Answer : a
Q61. Assertion (A): In microprocessor 8085 instruction LXIB, 90 FF H means register B and C are loaded with upper and lower bytes to get B = 90 H and C = FFH.

Reason (R): In 8085 the stack pointer indicates which memory location is to accessed.

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
Q62.To add 8 bit words, two IC 74181 can be cascaded.
a) True
b) False
Answer : a

Q63.The initial contents of ACC and CY in 8085 are

  1. CY = 1
  2. ACC = 10000001

After instruction RAL is executed once the contents of CY and ACC respectively will be

a) 1 and 00000011
b) 0 and 00000011
c) 1 and 00000001
d) 0 and 00000001
Answer : a
Q64. In 8085, which of the following is an 8 bit register?
a) A
b) SP
c) PC
d) both (a) and (b)
Answer : a
Q65. What does the instruction 'PCHL' in 8085 do?
a) Load the program counter with contents of register pair H L
b) Double the contents of register pair H L
c) Shift the contents of register pair H L by one bit to the right
d) Shift the contents of register pair H L by one bit to left
Answer : a
Q66. In a multi-processor configuration two coprocessors are connected to host 8086 processor. The instruction sets of the two coprocessors
a)  must be same
b) may overlap
c) must be disjoint
d) must be the same as that of host
Answer : d

Q67.Consider the following statements about constants in 8085

  1. The assembler treats 64 H as hexadecimal constant.
  2. The assembler treats 154 as binary constant.
  3. The assembler treats 540 as octal constant.
  4. The assembler treats 138 as decimal constant.

Which of the above are correct?

a)  1, 2 and 3 only
b) 1, 3 and 4 only
c) 1 and 3 only
d) 2 and 4 only
Answer : b
Q68. Internally the two distinct units of 8086 are called
a) bus interface unit and execution unit
b) command unit and follow unit
c) master unit and slave unit
d) memory unit and operation unit
Answer : a
Q69. Which of the following directives in 8085 causes one byte to be reserved in the memory?
a) D S
b) D B
c) D W
d) E Q U
Answer : d
Q70. The chip 8259 is a
a) programmable interrupt controller
b) programmable peripheral interface
c) I/O device
d) memory chip
Answer : a
Q71. In which group of 8085 instructions condition flags are not affected?
a) Data transfer group
b) Arithmetic group
c) Logical group
d) Both (a) and (c)
Answer : a
Q72. In 8085, the instruction CMA is an example of
a) Implict addressing
b) Direct addressing
c) Register addressing
d) Immediate addressing
Answer : a

Q73.Assertion (A): Static RAMS are used where speed of operation is of primary concern.

Reason (R): Dynamic RAM has lower cost per bit than static RAM.

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
Q74. In 8085 the time required to add two 32 bit numbers is (if clock frequency is 5 MHz)
a) about 1 ns
b) about 1 μs
c) about 30 μs
d) about 100 μs
Answer : c
Q75. Which of the following is not a classification of programmed data transfer?
a) Synchronous transfer
b) Hand shaking
c) Interrupt driver transfer
d) Direct transfer
Answer : d

Q76. Consider the instructions

  1. MOV M, B
  2. OUT 4
  3. LDA X

Which of the above uses IO/W cycle?

a) 1 only
b) 1 and 2 only
c) 2 only
d) 3 only
Answer : c
Q77. Which of the following is true?
a) Intel 8080 was the ancestor of Intel 8085
b) Intel 8080 was the ancestor of Intel Z 80
c) Intel 8080 was the ancestor of both Intel 8085 and Z 80
d)Intel 8085 was the ancestor of Intel 8085
Answer : c
Q78. For an accurate clock period in 8085 it is preferable to use
a) Crystal
b) Crystal or LC resonant circuit
c) Crystal or RC circuit
d) LC or RC circuit
Answer : a
Q79. The memory hierarchy in microprocessor based system is
a) register, cache, primary, mass, off line back up
b) cache, register, primary, mass, off line back up
c) cache, register, mass, primary, off line back up
d) register, cache, mass, primary, off line back up
Answer : a
Q80. When a peripheral device is not ready for data transfer it will send to the microprocessor a
a) low READY bit
b) high READY bit
c) low or high READY bit depending on whether input or output is activated
d) none of the above
Answer : a

Q81. Assertion (A): In microprocessor 8085 DMA allows direct access to memory to speed up data transfer.

Reason (R): HOLD and HLDA signals are used for DMA operations.

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
Q82. In 8085 the address space size is
a) 64 kbits
b) 64 k bytes
c) 32 kbits
d) 16 k bytes
Answer : b
Q83. In 8085 the instruction MOV A, B is an example of
a) Direct addressing
b) Immediate addressing
c) Register addressing
d) Register indirect addressing
Answer : c
Q84. In 8086
a)  the registers SI and DI are used for string operation
b) the registers CS and DS are used for string operation
c) the registers SS and ES are used for string operation
d) the registers SI and SP are used for string operation
Answer : a
Q85.  The organisation of Intel memory chip 127256 is
a) 32 K x 8
b) 16 K x 8
c) 32 K x 4
d) 16 K x 4
Answer : a
Q86. In a micro computer the control bus
a) transmits and receives control signals between processor and other devices
b) transmits and receives control signals, also sends and receives data
c) transmits and receives control signals, sends and receives data and transmits address of the device
d) none of the above
Answer : a
Q87. Which characteristics of a memory chip is called dc characteristics?
a) Organisation
b) Timing characteristics
c) Physical dimensions
d) Power consumption and bus loading
Answer : d
Q88. Consider the following strings
  1. A
  2. Z2
  3. X3Y
  4. P12R
  5. BX

Which of the above strings are valid in Pascal?

a) All
b) 1,2,3
c) 1,2,4,5
d) 1,2,3,5
Answer : a

Q89.  Consider the following statements

  1. In 8085 address and data buses are multiplexed.
  2. In Z 80 address and data buses are multiplexed
  3. In Z 80 address and data buses are not multiplexed.
  4. Z 80 has 16 bit address bus and 8 bit data bus.

Which of the above statements are correct?

a) 1 and 2 only
b) 1, 3 and 4 only
c) 1, 2 and 4 only
d) 2 and 4 only
Answer : c
Q90. The stack pointer holds the address of the desired memory location.
a) True
b) False
Answer : a
Q91. Which addressing mode is suitable only for these instructions in which there is only one operand?
a) Implicit
b) Register
c) Direct
d) Immediate
Answer :  a

Q92.Assertion (A): An instruction cycle consists of fetch and execute cycles.

Reason (R): Fetch cycle has one machine cycle but execute cycle may have one or more machine cycles depending on length of instruction.

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
Q93. In setting up ‘for’ loops in Pascal, the initial and final values of index may be
a) integer constants
b) Integer constants or integer variable names
c) integer constants or integer variable names or integer expressions
d) integer constants or real constants
Answer : c
Q94. In a 3 byte instruction of 8085, the first, second and third byte respectively indicate
a) operation code, low order byte of data/address and high order byte of data / address
b) low order byte of data / address, high order byte of data / address and operation code
c) high order byte of data / address, low order byte of data / address and operation code
d) high order byte of data / address, operation code and low order byte of data / address
Answer : a
Q95. Which of the following 8 bit microprocessors has maximum addressing modes?
a) 8085
b) Z 80
c) 6800
d) 6809
Answer : d

Q96. Consider the real expression in Pascal language

((X * Z) + Y/(M * P + K) + X)/Y + Y)

What would be evaluated first

a) XZ and MP + K
b) XZ + Y and MP + K
c) (MP + K + X) / Y
d) Y / (MP + K)
Answer : a

Q97. Consider the following

ON GO TO statement in Basic
35 ON A GO TO 15, 25, 35

If the value of A is 2.6, the control will transfer to

a) line 15
b) line 25
c) line 35
d) any of the lines 15 or 25, 35
Answer : b
Q98. The chip 8254 is a 40 pin programmable interval timer. The number of its independent 16 bit counters is
a) 2
b) 3
c) 4
d) 5
Answer : d
Q99.  For most static RAM the maximum access time is about
a) 1 ns
b) 10 ns
c) 100 ns
d) 1 μs
Answer : c
Q100. IC 7485 cannot be cascaded.
a) True
b) False
Answer : b