ISRO CS 2015

Question 11

The boolean expression AB + AB\'+ A\'C + AC is independent of the boolean variable

• A
• B
• C
• None of these

Question 12

If the sequence of operations - push (1), push (2), pop, push (1), push (2), pop, pop, pop, push (2), pop are performed on a stack, the sequence of popped out values

• 2,2,1,1,2

• 2,2,1,2,2

• 2,1,2,2,1

• 2,1,2,2,2

Question 13

A machine needs a minimum of 100 sec to sort 1000 names by quick sort. The minimum time needed to sort 100 names will be approximately

• 50.2 sec
• 6.7 sec
• 72.7 sec
• 11.2 sec

Question 14

Six files F1, F2, F3, F4, F5 and F6 have 100, 200, 50, 80, 120, 150 records respectively. In what order should they be stored so as to optimize act. Assume each file is accessed with the same frequency

• F3, F4, F1, F5, F6, F2

• F2, F6, F5, F1, F4, F3

• F1, F2, F3, F4, F5, F6

• Ordering is immaterial as all files are accessed with the same frequency.

Question 15

Which searching technique takes O(1) time complexity for searching the data?

• Binary Search

• Linear Search

• AVL Tree Search

• Hashing

Question 16

The queue data structure is to be realized by using stack. The number of stacks needed would be

• It cannot be implemented
• 2 stacks
• 4 stacks
• 1 stack

Question 17

Consider the following Relationship Entity Diagram(ERD) Which of the following possible relations will not hold if the above ERD is mapped into a relation model?

• Person (NID, Name)
• Qualification (NID, ExamID, QualifiedDate)
• Exam (ExamID, NID, ExamName)
• Exam (ExamID, ExamName)

Question 18

Consider the following log sequence of two transactions on a bank account, with initial balance 12000, that transfer 2000 to a mortgage payment and then apply a 5% interest. 1. T1 start 2. T1 B old=1200 new=10000 3. T1 M old=0 new=2000 4. T1 commit 5. T2 start 6. T2 B old=10000 new=10500 7. T2 commit Suppose the database system crashes just before log record 7 is written. When the system is restarted, which one statement is true of the recovery procedure?

• We must redo log record 6 to set B to 10500

• We must undo log record 6 to set B to 10000 and then redo log records 2 and 3

• We need not redo log records 2 and 3 because transaction T1 has committed

• We can apply redo and undo operations in arbitrary order because they are idempotent.

Question 19

Given a block can hold either 3 records or 10 key pointers. A database contains n records, then how many blocks do we need to hold the data file and the dense index

• 13n/30
• n/3
• n/10
• n/30

Question 20

The maximum length of an attribute of type text is

• 127

• 255

• 256

• It is variable