A directory of Objective Type Questions covering all the Computer Science subjects. Here you can access and discuss Multiple choice questions and answers for various compitative exams and interviews.

91. Identify the devices given below with their IC numbers :

(i) USART                                 (a) 8251
(ii) Micro controller                (b) 8051
(iii) Interrupt controller         (c) 8259
(iv) DMA controller                 (d) 8257

      (i)   (ii)    (iii) (iv)
a. (a)  (b)   (c)  (d)
b. (b)  (a)   (d)  (c)
c. (c)  (d)   (a)  (b)
d. (d)  (a)   (b)  (c)
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Answer: (a).(a)  (b)   (c)  (d)

92. On receiving an interrupt from an I/O device, the CPU
a. halts for predetermined time.
b. branches off to the interrupt service routine after completion of the current instruction.
c. branches off to the interrupt service routine immediately.
d. hands over control of address bus and data bus to the interrupting device.
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Answer: (b).branches off to the interrupt service routine after completion of the current instruction.

93. Consider a logical address space of 8 pages of 1024 words mapped with memory of 32 frames. How many bits are there in the physical address?
a. 9 bits
b. 11 bits
c. 13 bits
d. 15 bits
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Answer: (d).15 bits

94. CPU does not perform the operation
a. data transfer
b. logic operation
c. arithmetic operation
d. all of the above
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Answer: (d).all of the above

95. A chip having 150 gates will be classified as
a. SSI
b. MSI
c. LSI
d. VLSI
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Answer: (b).MSI

96. A latch is constructed using two cross-coupled
a. AND and OR gates
b. AND gates
c. NAND and NOR gates
d. NAND gates
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Answer: (d).NAND gates

97. An astable multivibrator has
a. one stable state
b. two stable states
c. no stable states
d. none of these
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Answer: (c).no stable states

98. The register or main memory location which contains the effective address of the operand is known as
a. pointer
b. special location
c. indexed register
d. None of the above
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Answer: (a).pointer

99. The logic expression for the output of the circuit shown in the figure is
logic expression
a. A’C’+B’C’+CD
b. AC’+BC’+C’D
c. ABC+C’D’
d. A’B’+B’C’+C’D’
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Answer: (c).ABC+C’D’

100. Advantage of synchronous sequential circuits over asynchronous ones is
a. faster operation
b. ease of avoiding problems due to hazard
c. lower hardware requirement
d. better noise immunity
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Answer: (a).faster operation