UGC NET COMPUTER SCIENCE SOLVED PAPERS 2017-19 - UGC NET Computer Science November 2017 Paper 3

1. In 8085 microprocessor which of the following flag(s) is (are) affected by an arithmetic operation ?

  • Option : D
  • Explanation :
    AC is auxiliary-Carry flag, CY is Carry flag and Z is Zero flag. All these flags will be affected during arithmetic operation. So, option (D) is correct.
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2. In 8085 microprocessor the address bus is of __________ bits.

  • Option : C
  • Explanation :
    In 8085 microprocessor 16 bits are used for address bus and 65,536(216 = 65,536) different memory location are possible. So, option (C) is correct.
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3. In the architecture of 8085 microprocessor match the following:

(a) Processing Unit    (i) Interrupt
(b) Instruction unit   (ii) General Purpose Register
(c) Storage and Interface unit  (iii) ALU
  (iv) Timing and Control
 Code:
 (a)(b)(c)
(1)(iv)(i)(ii)
(2)(iii)(iv)(ii)
(3)(ii)(iii)(i)
(4)(i)(ii)(iv)

  • Option : B
  • Explanation :
  • ALU is the arithmetic logic unit and it involves processing of input into desired output.
  • Timing and control instruction are covered in instruction unit of microprocessor.
  • There are some general purpose register in storage and interface unit.
  • While an interrupt is a signal to the processor which required attention from processor, an interrupt is serviced on the basis of priorty and need.
  • So, option (B) is correct.
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4. Which of the following addressing mode is best suited to access elements of an array of contiguous memory locations ?

  • Option : A
  • Explanation :
    Indexed addressing mode is best suited for accessing an array in contiguous memory location. For detailed information on addressing modes Refer:Addressing_Modes. So, option (A) is correct.
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5. Which of the following is correct statement ?

  • Option : B
  • Explanation :
  • The isolated I/O method isolates memory and I/O addresses so that memory address range is not affected by interface address assignment.
  • Memory based I/O uses same address space for memory and I/O devices.
  • In asynchronous serial transfer of data the two units do not share a common clock.
  • In synchronous serial transfer of data the two units share a common clock.
  • Refer:I/O interface Option (B) is correct.
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