A free IBPS SO IT Mains mock test is a timed practice paper based on the Professional Knowledge (IT) section of the IBPS Specialist Officer (IT Officer) Mains exam. It helps you check your speed, accuracy and weak topics before the real exam.
In this article you get 20 medium-level questions with answers and step-by-step solutions. They are taken from our full 40-question mock test: IBPS SO IT Mains – Full Syllabus Professional Knowledge Mock Test 1. You also get a short revision of the key concepts used in these questions.
Mock Test at a Glance
| Detail | Information |
|---|---|
| Exam | IBPS SO IT Officer – Mains |
| Section | Professional Knowledge (IT) |
| Sector | Banking & Finance |
| Difficulty | Medium |
| Full Mock Test | 40 questions, 40 marks, 40 minutes |
| In this article | 20 selected questions with solutions |
| Cost | Free |
Topics covered: Database Management Systems, Computer Networks, Operating Systems, Data Structures & Algorithms, Software Engineering, and Cyber Security.
Important Concepts to Revise Before You Start
Spend 10 minutes on these core points before solving the questions:
1. Database Management Systems (DBMS)
- Foreign key join: If every foreign key value in table R is non-NULL and matches a primary key in table S, then the natural join has exactly as many rows as R.
- Isolation levels: Read Uncommitted allows all problems. Read Committed stops dirty reads. Repeatable Read also stops non-repeatable reads. Serializable stops phantom reads too.
- 3NF vs BCNF: A relation is in 3NF if, for every dependency X → Y, either X is a superkey or Y is a prime attribute. BCNF needs X to be a superkey always.
- Conflict serializability: Draw a precedence graph. If it has a directed cycle, the schedule is not conflict serializable.
2. Computer Networks
- Subnetting: Usable hosts = 2^h − 2, where h is the number of host bits. Mask length = 32 − h.
- TTL (Time to Live): An 8-bit field that reduces by 1 at every router hop. At 0, the packet is dropped. This prevents endless routing loops.
- Split Horizon: A rule in distance vector protocols (like RIP) that prevents the count-to-infinity problem.
- TCP Tahoe: On timeout, ssthresh = cwnd / 2 and cwnd = 1 MSS, restarting Slow Start.
3. Operating Systems
- Round Robin: Each process gets a fixed time quantum. Waiting time = Turnaround time − Burst time.
- Deadlock-free condition: With N processes each needing at most M instances, the system is safe if resources ≥ N × (M − 1) + 1.
- Belady's Anomaly: More frames can cause more page faults in FIFO replacement.
- Thrashing: The system spends more time swapping pages than running processes.
4. Data Structures & Algorithms
- BST traversal: The inorder traversal of a BST is always sorted. The first element of preorder is the root.
- Postfix evaluation: Use a stack. Pop two operands for each operator. The exponent operator is right-associative.
- QuickSort worst case: O(n²). It occurs when the pivot is always the smallest or largest element (such as a sorted list with the first element as pivot).
- AVL tree: Balance factor must be −1, 0 or +1. An LL imbalance is resolved with a single right rotation.
5. Software Engineering
- Cyclomatic complexity: V(G) = E − N + 2P.
- Boundary Value Analysis: Test values just below, on, and just above each boundary.
6. Cyber Security
- Digital signature: The signer signs with their private key. Anyone verifies with the signer's public key.
- SQL Injection defence: Always use parameterized queries (PreparedStatements).
Free IBPS SO IT Mains Mock Test: 20 Questions with Answers
Try answering each question within 40 seconds before viewing the solution.
Section A: Database Management Systems
Q1· Database Management Systems
Table R has 40 tuples and Table S has 60 tuples. Attribute A is a foreign key in R referencing the primary key A in S, and no foreign key value in R is NULL. What are the minimum and maximum number of tuples in the natural join of R and S?
AMin = 0, Max = 40
BMin = 40, Max = 40
CMin = 40, Max = 60
DMin = 40, Max = 2400
Q2· Database Management Systems
In SQL, which standard isolation level prevents both Dirty Reads and Non-Repeatable Reads, but still allows Phantom Reads?
AREAD UNCOMMITTED
BREAD COMMITTED
CREPEATABLE READ
DSERIALIZABLE
Q3· Database Management Systems
A relation R(A, B, C, D) has the functional dependencies F = {AB → C, C → D, D → A}. What is the highest normal form satisfied by R?
A1NF
B2NF
C3NF
DBCNF
Q4· Database Management Systems
Consider a schedule S with two transactions T1 and T2: r1(X); w2(X); r2(Y); w1(Y);. What does the precedence graph of S show?
AAcyclic graph; schedule is conflict serializable
BDirected cycle exists; schedule is NOT conflict serializable
CSchedule is both view serializable and conflict serializable
DSchedule causes immediate cascade rollback
Click to enlarge
Section B: Computer Networks
Q5· Computer Networks
A bank network administrator must create subnets for 4 branch offices. Each branch needs 28 usable host IP addresses. The block 192.168.10.0/24 is available. What subnet mask should be configured on the branch routers?
A255.255.255.192 (/26)
B255.255.255.240 (/28)
C255.255.255.224 (/27)
D255.255.255.248 (/29)
Q6· Computer Networks
What is the main function of the Time to Live (TTL) field in an IPv4 packet header?
ATo prevent data packets from looping endlessly in the network
BTo record the timestamp of packet generation
CTo specify the end-to-end transport delivery timeout
DTo negotiate maximum transmission unit (MTU)
Q7· Computer Networks
Which routing problem is reduced by the Split Horizon rule in Distance Vector protocols such as RIP?
ASubnet broadcast storms
BCount-to-Infinity problem
CTCP SYN-flood denial of service
DJitter in real-time traffic
Q8· Computer Networks
A TCP connection is in the Congestion Avoidance phase with a congestion window of 16 MSS. A timeout occurs. What are the new values of ssthresh and cwnd according to TCP Tahoe?
Assthresh = 8 MSS, cwnd = 1 MSS
Bssthresh = 8 MSS, cwnd = 8 MSS
Cssthresh = 16 MSS, cwnd = 1 MSS
Dssthresh = 8 MSS, cwnd = 4 MSS
Section C: Operating Systems
Q9· Operating Systems
Three processes arrive at t = 0 ms: P1 (burst time 6 ms), P2 (4 ms) and P3 (2 ms). Under Round Robin scheduling with time quantum 2 ms, what is the average waiting time?
A5.33 ms
B4.67 ms
C6.00 ms
D5.00 ms
Q10· Operating Systems
A system has 4 processes sharing one resource type. The maximum demand of each process is 4 instances. What is the minimum number of resource instances needed to guarantee that the system never enters a deadlock?
A11
B12
C13
D16
Q11· Operating Systems
Which page replacement algorithm can show an increase in page faults when the number of allocated frames increases (Belady's Anomaly)?
ALeast Recently Used (LRU)
BFirst-In, First-Out (FIFO)
COptimal Replacement (OPT)
DLeast Frequently Used (LFU)
Q12· Operating Systems
What do we call the situation when an operating system spends much more time swapping pages in and out of secondary storage than executing user instructions?
AAging
BBelady's Anomaly
CThrashing
DSegmentation Fault
Section D: Data Structures & Algorithms
Q13· Data Structures & Algorithms
The preorder traversal of a Binary Search Tree is: 40, 20, 10, 30, 60, 50, 70. What is the height of this BST (number of edges on the longest root-to-leaf path)?
A1
B2
C3
D4
Q14· Data Structures & Algorithms
Evaluate this postfix expression, where ^ is the right-associative exponent operator: 2 3 2 ^ ^ 5 +
A69
B73
C261
D517
Q15· Data Structures & Algorithms
What is the worst-case time complexity of QuickSort on n elements when the pivot is always the first element and the input is already sorted?
AO(n log n)
BO(n²)
CO(n)
DO(log n)
Q16· Data Structures & Algorithms
Keys 30, 20 and 10 are inserted in this order into an empty AVL tree. Which rotation restores balance, and what is the new root?
ASingle Right Rotation; root becomes 20
BSingle Left Rotation; root becomes 20
CLeft-Right Double Rotation; root becomes 10
DRight-Left Double Rotation; root becomes 30
Section E: Software Engineering
Q17· Software Engineering
A control flow graph G has 14 edges, 10 nodes and 1 connected component. What is the McCabe Cyclomatic Complexity V(G)?
A4
B5
C6
D8
Q18· Software Engineering
An online savings account module accepts age from 18 to 60 years (both included). Using standard Boundary Value Analysis, which set of test inputs should you choose?
A18, 30, 60
B17, 18, 60, 61
C0, 18, 60, 100
D17, 18, 19, 59, 60, 61
Section F: Cyber Security & Cryptography
Q19· Cyber Security & Cryptography
In a bank's digital certificate system, User A verifies a digital signature created by User B on a loan agreement. Which key must User A use to decrypt the signature?
AUser A's Private Key
BUser A's Public Key
CUser B's Private Key
DUser B's Public Key
Q20· Cyber Security & Cryptography
Which technique gives the most effective defence against SQL Injection in database-driven banking applications?
AClient-side JavaScript input validation
BParameterized queries with PreparedStatement
CEncrypting the backend database with BitLocker
DDeploying an intrusion detection system (IDS)
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How to Use This Mock Test to Score Better
- Revise the concepts first: Read the short concept summary above for 10 minutes.
- Solve with a timer: Aim for about 40 seconds per question.
- Mark weak topics: Note every question you got wrong and review that subject area.
- Read every solution: Even for correct answers, look for a faster approach.
- Retake after revision: Attempt the full 40-question test again after 3 to 4 days.
Final Words
Regular practice with timed mock tests is the best way to improve your speed and accuracy in the IBPS SO IT Mains Professional Knowledge section. Revise the key concepts, solve these 20 questions, and then take the full 40-question free mock test in the live test room.
All the best for your preparation!