Introduction
UGC NET Exam is a very popular exam in India for people interested in research. Previous Year Questions are an excellent option to learn about the exam pattern. By solving the PYQs, you will get a basic idea about your preparation.
Refer to July 2018 Paper II Part 1 here.
Refer to July 2018 Paper II Part 2 here.
Refer to July 2018 Paper II Part 4 here.
You can evaluate your weak areas and work on them to perform better in the examination. In this article, we have given the questions of UGC NET July 2018 Paper II. We have also explained every problem adequately to help you learn better.
July 2018 Paper II Part 3
51. At a particular computation time, the value of a counting semaphore is 10. Then 12 P operations and “x” V operations were performed on this semaphore. If the final value of the semaphore is 7, x will be:
(1) 8
(2) 9
(3) 10
(4) 11
Answer: 2
Initially, the value of a counting semaphore is 10 Now 12 P operations are performed.
Now counting semaphore value = -2
“x” V operations were performed on this semaphore and final value of counting semaphore = 7
i.e x + (-2) = 7
x = 9.
52. In a paged memory, the page hit ratio is 0.40. The time required to access a page in secondary memory equals 120 ns. The time required to access a page in primary memory is 15 ns. The average time required to access a page is ..................
(1) 105
(2) 68
(3) 75
(4) 78
Answer: 4
Average access time = hit ratio * primary memory access time + (1 – hit ratio) * secondary memory access time
Average access time = 0.4 * 15 + 0.6 * 120
Average access time = 6 + 72
Average access time = 78.
53. In a multi-user operating system, 30 requests are made to use a particular resource per hour, on average. The probability that no requests are made in 40 minutes when the arrival pattern is a Poisson distribution is ...............
(1) e−15
(2) 1−e−15
(3) 1−e−20
(4) e−20
Answer: 4
No. of request in 60 minutes = 30
No. of request in 1 minute = 0.5
p = No. of request should be made in 40 minutes = 40 * 0.5 = 20
x = But In Reality How many Request in 40 minutes = 0
Poison’s Distribution = (e−20∗200)/0! = e−20
54. Normally user programs are prevented from handling I/O directly by I/O instructions in them. For CPUs having explicit I/O instructions, such I/O protection is ensured by having the I/O instructions privileged. In a CPU with memory-mapped I/O, there is no explicit I/O instruction. Which one of the following is true for a CPU with memory-mapped I/O?
(1) I/O protection is ensured by operating system routines.
(2) I/O protection is ensured by a hardware trap.
(3) I/O protection is ensured during system configuration.
(4) I/O protection is not possible.
Answer: 1
User applications are not allowed to perform I/O in user mode – All I/O requests are handled through system calls that must be performed in kernel mode.
55. Which UNIX/Linux command is used to make all files and sub-directories in the directory “progs” executable by all users?
(1) chmod −R a+x progs
(2) chmod −R 222 progs
(3) chmod −X a+x progs
(4) chmod −X 222 progs
Answer: 1
chmod− R a+x progs is used to make all files and sub-directories in the directory “progs” executable by all users.
56. Which of the following statements are true?
(a) External Fragmentation exists when there is enough total memory space to satisfy a request, but the available space is contiguous.
(b) Memory Fragmentation can be internal as well as external.
(c) One solution to external Fragmentation is compaction.
Code:
(1) (a) and (b) only
(2) (a) and (c) only
(3) (b) and (c) only
(4) (a), (b) and (c)
Answer: 3
External Fragmentation exists when there is enough total memory space to satisfy a request, but the available space is contiguous. This is a false statement because external fragmentation occurs due to non-contigious available space.
Memory Fragmentation can be internal as well as external. True
One solution to external Fragmentation is compaction or shuffling memory contents. True
57. Page information in memory is also called a Page Table. The essential contents in each entry of a page table are ....................
(1) Page Access information
(2) Virtual Page number
(3) Page Frame number
(4) Both virtual page number and Page Frame Number
Answer: 3
Page information in memory is also called a Page Table. The essential contents in each entry of a page table are the page frame number.
58. Consider a virtual page reference string 1, 2, 3, 2, 4, 2, 5, 2, 3, 4. Suppose the LRU page replacement algorithm is implemented with 3-page frames in the main memory. Then the number of page faults is.................
(1) 5
(2) 7
(3) 9
(4) 10
Answer: 2
Option 2 will be the correct option.
59. Consider the following three processes with the arrival time and CPU burst time given in milliseconds:
The Gantt Chart for preemptive SJF scheduling algorithm is ...............
Answer: 2
P1 arrive at 0 it will be served by CPU for 1 unit. After 1 unit P2 arrived ans it is shortest So it will execute for 4 unit, after its execution There are 2 processes out of which P1 is shortest so it will execute for 6 unit after its execution P1 will execute for 8 unit.
Gantt chart for preemptive SJF scheduling algorithm is shown in option 2;
60. In which of the following scheduling criteria, context switching will never take place?
(1) ROUND ROBIN
(2) Preemptive SJF
(3) Non-preemptive SJF
(4) Preemptive priority
Answer: 3
In Non – preemptive algorithms context switching will never take place because it doesn’t allow to switch the process until it is completed fully.
61. In RDBMS, which type of Join returns all rows that satisfy the join condition?
(1) Inner Join
(2) Outer Join
(3) Semi Join
(4) Anti Join
Answer: 1
In RDBMS, the inner join returns all rows that satisfy the given join condition.
62. Consider a relation book (title, price) which contains the titles and prices of different books. Assuming that no two books have the same price, what does the following SQL query list?
Select title
from book as B
where (select count (*)
from book as T
where T.price > B.price) < 7
(1) Titles of the six most expensive books.
(2) Title of the sixth most expensive books.
(3) Titles of the seven most expensive books.
(4) Title of the seventh most expensive books.
Answer: 3
When a subquery uses values from the outer query, the subquery is called correlated subquery. The correlated subquery is evaluated once for each row processed by the outer query.
The outer query selects all titles from the book table. For every selected book, the subquery returns the count of those books which are more expensive than the selected book. The where clause of the outer query will be true for the 5 most expensive books. For example count (*) will be 0 for the most expensive book and count(*) will be 1 for the second most expensive book.
63. In a Hierarchical database, a hashing function is used to locate the .................
(1) Collision
(2) Root
(3) Foreign Key
(4) Records
Answer: 2
In a Hierarchical database, a hashing function is used to locate the root.
64. Relations produced from E - R Model will always be in ..............
(1) 1 NF
(2) 2 NF
(3) 3 NF
(4) 4 NF
Answer: 3
As we know that every table is already in 1NF. and relations produced from the E – R Model will always be a table which is in 1Nf.
65. Consider the following schedules involving two transactions.
S1 : r1(X) ; r1(Y) ; r2(X) ; r2(Y) ; w2(Y) ; w1(X)
S2 : r1(X) ; r2(X) ; r2(Y) ; w2(Y) ; r1(Y) ; w1(X)
Which one of the following statements is correct with respect to above?
(1) Both S1 and S2 are conflict serialisable.
(2) Both S1 and S2 are not conflicted serialisable.
(3) S1 is conflict serializable and S2 is not conflict serializable.
(4) S1 is not conflict serializable and S2 is conflict serializable.
Answer: 4
S1 is not conflict serializable, but S2 is conflict serializable
Schedule S1
T1 T2
---------------------
r1(X)
r1(Y)
r2(X)
r2(Y)
w2(Y)
w1(X)
The schedule is neither conflict equivalent to T1T2, nor T2T1.
Schedule S2
T1 T2
---------------------
r1(X)
r2(X)
r2(Y)
w2(Y)
r1(Y)
w1(X)
The schedule is conflict equivalent to T2T1.
66. For a database relation R(a, b, c, d) where the domains of a, b, c and d include only atomic values, and only the following functional dependencies and those that can be inferred from them hold:
a → c
b → d
The relation is in ...............
(1) First normal form but not in second normal form
(2) Second normal form but not in third normal form
(3) Third normal form
(4) BCNF
Answer: 1
Candidate Key of above relation is:- ab only.
a and b is a partial attribute (part of the CK) that’s why the given FD is partially dependent.
In 2NF there must not be partially dependent FD and we know that every table is already in 1NF.
Hence, this relation is in the first normal form but not in the second normal form.
67. A many-to-one relationship exists between entity sets r1 and r2. How will it be represented using functional dependencies if Pk(r) denotes the primary key attribute of relation r?
(1) Pk(r1) → Pk(r2)
(2) Pk(r2) → Pk(r1)
(3) Pk(r2) → Pk(r1) and Pk(r1) → Pk(r2)
(4) Pk(r2) → Pk(r1) or Pk(r1) → Pk(r2)
Answer: 1
A many to one relationship set exists between entity sets Employee and Department.
Let two relations R1(employee with pk empId)
R2(Department with pk DId)
Here, empId can uniquely identify DId but DId can not uniquely identify the empId.
Hence, pk(R1) -> pk(R2)
68. Database systems that store each relation in a separate operating system file may use the operating system’s authorisation scheme instead of defining a special scheme themselves. In this case, which of the following is false?
(1) The administrator enjoys more control over the grant option.
(2) It is difficult to differentiate between the update, delete and insert authorisations.
(3) Cannot store more than one relationship in a file.
(4) Operations on the database are speeded up as the authorisation procedure is carried out at the operating system level.
Answer: 1
Database systems that store each relation in a separate operating system file may use the operating system’s authorization scheme, instead of defining a special scheme themselves. In this case:
The administrator enjoys more control over the grant option true
It is difficult to differentiate between the update, delete and insert authorizations. True
We cannot store more than one relationship in a file. True
Operations on the database are speeded up as the authorization procedure is carried out at the operating system level. False
69. Let R1(a, b, c) and R2(x, y, z) be two relations in which a is the foreign key of R1 that refers to the primary key of R2. Consider the following four options.
(a) Insert into R1 (b) Insert into R2
(c) Delete from R1 (d) Delete from R2
Which of the following is correct about the referential integrity constraint with respect to
above?
(1) Operations (a) and (b) will cause violation.
(2) Operations (b) and (c) will cause violation.
(3) Operations (c) and (d) will cause violation.
(4) Operations (d) and (a) will cause violation.
Answer: 4
Let x is the primary key in R2(x, y, z)
Insert into R1 – This can cause violation because if we want to insert any value into a of R1, which is not in x of R2.
Insert into R2 – Can not cause violation
Delete from R1 – Can not cause a violation.
Delete from R2 – This can cause a violation if we delete any value of x in R2, then the value referred by a in R1 should also be deleted.
70. Consider a hash table of size seven, with starting index zero, and a hash function (7x+3) mod 4. Assuming the hash table is initially empty, which of the following is the contents of the table when the sequence 1, 3, 8, 10 is inserted into the table using closed hashing? Here “__” denotes an empty location in the table.
(1) 3, 10, 1, 8, __, __, __
(2) 1, 3, 8, 10, __, __, __
(3) 1, __, 3, __, 8, __, 10
(4) 3, 10, __, __, 8, __, __
Answer: 1
Keys are 1, 3, 8, 10.
h(x) = (7*x + 3)
h(1) = (10) mod 4 = 2
h(3) = (7 * 3 + 3) mod 4 = 24 mod 4 = 0
h(8) = (7 * 8 + 3) mod 4 = 3
h(10)= (7 * 10 + 3)mod 4 = 1
i.e. 3, 10, 1, 8, __ , __ , __
71. In Artificial Intelligence (AI), an environment is uncertain if it is ..............
(1) Not fully observable and not deterministic
(2) Not fully observable or not deterministic
(3) Fully observable but not deterministic
(4) Not fully observable but deterministic
Answer: 2
The correct option is 2.
72. In Artificial Intelligence (AI), a simple reflex agent selects actions on the basis of ...................
(1) current percept, completely ignoring the rest of the percept history.
(2) rest of the percept history, completely ignoring the current percept.
(3) both current percept and complete percept history.
(4) both current percept and just previous percept.
Answer: 1
Option 1 is the correct option.
73. In heuristic search algorithms in Artificial Intelligence (AI), if a collection of admissible heuristics h1.......hm is available for a problem and none of them dominates any of the others, which should we choose?
(1) h(n)=max{h1(n),....,hm(n)}
(2) h(n)=min{h1(n),....,hm(n)}
(3) h(n)=avg{h1(n),....,hm(n)}
(4) h(n)=sum{h1(n),....,hm(n)}
Answer: 1
In heuristic search algorithms in Artificial Intelligence (AI), if a collection of admissible heuristics h 1 …….hm is available for a problem and none of them dominates any of the others then h(n)=max{h1 (n),….,h m (n)}.
74. Consider the following sentences regarding A*, an informed search strategy in Artificial Intelligence (AI).
(a) A* expands all nodes with f(n) < C*.
(b) A* expands no nodes with f(n) /C*.
(c) Pruning is integral to A*.
Here, C* is the cost of the optimal solution path.
Which of the following is correct with respect to the above statements?
(1) Both statement (a) and statement (b) are true.
(2) Both statement (a) and statement (c) are true.
(3) Both statement (b) and statement (c) are true.
(4) All the statements (a), (b) and (c) are true.
Answer: 2
Option 2 is the correct answer.
75. Consider a vocabulary with only four propositions A, B, C and D. How many models are there for the following sentence?
B V C
(1) 10
(2) 12
(3) 15
(4) 16
Answer: 2
There are four variables A, B, C, and D. Therefore 2^4 = 16.
From 0 to 15 models are exist, but one is 0, so 15 is the correct answer.