PSC HSST Computer Science Model Questions and Answers – Part 5

76. From a table STUDENT with the fields ROLLNO., NAME, MARK1, MARK2 and MARK3, which of the following SQL command lists student with the highest mark in mark1 field?
(A) SELECT ROLLNO, MARK1 FROM STUDENT ORDER BY MARK1
(B) SELECT ROLLNO, MARK1 FROM STUDENT GROUP BY MARK1
(C) SELECT ROLLNO, MARK1 FROM STUDENT WHERE MARK1= SELECT MAX(MARK1) FROM STUDENT
(D) None of the above
Answer: C

77. If A→BC, B→E and CD→EF hold in a relation scheme R(A,B,C,D,E,F). Which of the following functional dependencies also hold?
(A) B→D (B) AD→CD
(C) D→A (D) B→C
Answer: B

78. In a relation scheme R with attributes A, B, C which of the following defines the augmentation property?
(A) if A→B holds, then AC→BC where C is a subset of R
(B) A→B and B→C implies A→C
(C) If A→B holds, then B→A also hold
(D) X→YZ implies X→Y and X→Z
Answer: A

79. Spurious tuples may occur due to
(i) Bad normalization
(ii) Theta joins
(iii) Updating tables from join
(A) (ii) or (iii) (B) (ii) and (iii)
(C) (i) and (iii) (D) (i) or (iii)
Answer: C

80. Which of the following data structure is widely used in a network model RDBMS?
(A) Arrays (B) Graphs
(C) Trees (D) Stacks
Answer: B

81. Tables derived from the ER diagram are:
(A) are totally unnormalized (B) are always in 1NF
(C) can be further denormalized (D) may have multivalued attribute
Answer: B

82. A non-linear data structure from among the set given below is:
(A) queue (B) stack
(C) linked list (D) tree
Answer: D

83. The equivalent prefix expression corresponding to the infix expression (a+b)*(c+d)-g+h is:
(A) +-+ab+cd*gh (B) +ab*+cd-g+h
(C) +-*+abcd+gh (D) +-*+ab+cdgh
Answer: D

84. In a complete binary tree of depth n, the difference between the number of nodes at level n and level n-1 is:
(A) 2(n-1) (B) 2n
(C) 2(n-2) (D) 2n-1
Answer: A

85. A binary tree with 20 nodes can have ……………. null branches (A null branch is a branch pointed to by a null pointer, if represented by a linked list structure).
(A) 20 (B) 21
(C) 10 (D) 9
Answer: B

86. How many distinct binary trees are possible with n nodes?
(A) 2n-n (B) n!
(C) n!-n (D) 2n
Answer: A

87. Which among the following is the average case complexity of the quick sort algorithm?
(A) O(log n) (B) O(n2)
(C) O(n log n) (D) O(log n2)
Answer: C

88. A common property of the selection sort and quick sort algorithm is:
(A) an in place sorting method
(B) best case is of O(n) complexity
(C) average is of O(n log n) complexity
(D) worst case of O(n log n) complexity
Answer: A

89. Which of the following algorithms has running time O(n2) in the worst case but O(n logn) on average?
(A) bubble sort (B) merge sort
(C) heap sort (D) quick sort
Answer: D

90. What is the worst case complexity of Quick-sort?
(A) O(log n) (B) O(n log n)
(C) O(n2) (D) O(n)
Answer: C

91. Minimum cost spanning tree algorithm uses a technique of:
(A) Greedy method (B) divide and conquer
(C) Dynamic programming (D) randomized technique
Answer: A

92. A binary search tree with 8 nodes produced 1,2,3,4,5,6,7,8 as the inorder reversal. What is the root node of the tree?
(A) 1 (B) 5
(C) 8 (D) cannot be determined
Answer: D

93. Which among the following is incorrect about the complexity of algorithms?
(A) O(n)<O(n log n)<O(n2)
(B) O(log n)<O(n log n)<O(n2)
(C) O(log n)<O(n)<O(n2)
(D) O(n)<O(log n)<O(n2)
Answer: D

94. Which among the following devices interconnects networks and operate at the application layer?
(A) bridge (B) hub
(C) router (D) gateway
Answer: D

95. There is diskless workstation on a TCP/IP LAN. Which will be the first protocol it will use?
(A) FTP (B) ARP
(C) HTTP (D) RARP
Answer: D

96. Modems communicating using the V.32 bis standard operate at:
(A) 9600 bps (B) 14400 bps
(C) 28800 bps (D) 56000 bps
Answer: B

97. RS-449 is a standard used for:
(A) Serial communication (B) parallel communication
(C) Network signaling (D) modem signaling
Answer: A

98. The polynomial used by CRC – 16 standard for generating the checksum is:
(A) x16+ x12+ x5+1 (B) x15+ x12+ x6+1
(C) x16+ x15+ x2+1 (D) x12+ x6+ x5+1
Answer: C

99. Which among the following is not part of the TCP header of a TCP/IP packet?
(A) Sequence number (B) Acknowledgement number
(C) Window size (D) Protocol
Answer: D

100. The IP address of a node on a LAN based on TCP/IP is 191.168.10.1. Into which class does this address belong?
(A) class A (B) class B
(C) class C (D) class D
Answer: B