All 100 questions of DSSSB TGT Computer Science PYQ (Technical), 13 Sep 2025, Shift 3 (5:00 PM) with the correct answer from the official answer key and a solution. Read them free on UTpaper, or attempt the paper as a timed online test.
Which of the following mechanisms ensures that data is NOT duplicated after crash
recovery?
ASequence numbers and acknowledgments
BPort numbers
CTimeouts
DWindow size adjustment
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Correct answer: (A) Sequence numbers and acknowledgments
Explanation
TCP numbers every byte with sequence numbers and confirms receipt with acknowledgments. After recovery, the receiver can then detect and discard duplicate segments.
Which of the following statements correctly updates the Bill column in the Customer table by
applying a 10% discount only for customers who belong to the 'High privilege' account?
AMODIFY Customer SET Bill = Bill / 1.1 WHERE Account = 'High privilege';
BUPDATE Customer SET Bill = Bill / 1.1;
CUPDATE Customer SET Bill = Bill / 1.1 WHERE Account = 'High privilege';
Correct answer: (C) UPDATE Customer SET Bill = Bill / 1.1 WHERE Account = 'High privilege';
Explanation
UPDATE ... SET ... WHERE changes only the rows that match. Dividing by 1.1 gives the discounted bill, and the WHERE clause limits it to 'High privilege' accounts. MODIFY is not DML, and B has no WHERE.
What is the output of the following SQL command if the subquery returns no rows?
DELETE FROM Product WHERE ProductID IN (SELECT ProductID FROM ArchivedProduct
WHERE Status = 'Sell');
ANo rows are deleted
BAll rows in Product are deleted
CRows will be deleted from ArchivedProduct
DError
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Correct answer: (A) No rows are deleted
Explanation
If the subquery returns no rows, the IN list is empty and the condition is false for every row, so no rows are deleted from Product and no error occurs.
Which of the following statements is true about TRUNCATE in SQL (Structured Query
Language)?
ATRUNCATE removes table structure.
BTRUNCATE does not remove data from the table.
CTRUNCATE is a DML command.
DTRUNCATE is faster than DELETE.
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Correct answer: (D) TRUNCATE is faster than DELETE.
Explanation
TRUNCATE removes all rows at once with little logging and no row-by-row triggers, so it is faster than DELETE. It keeps the table structure and is a DDL command.
Which of the following is NOT a benefit of using threads in an operating system?
AImproved application responsiveness
BIncreased system resource utilisation
CSimplified programming model
DFaster execution of tasks in single-core processors
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Correct answer: (D) Faster execution of tasks in single-core processors
Explanation
On a single-core CPU, threads only take turns (concurrency), so they do not make tasks run faster in parallel. They do improve responsiveness and resource use.
What is the advantage of using a sliding window over a stop-and-wait protocol?
ASliding window is simpler to implement.
BSliding window uses larger packet sizes.
CSliding window increases throughput by allowing multiple packets to be sent before
acknowledgment.
DSliding window requires no acknowledgments.
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Correct answer: (C) Sliding window increases throughput by allowing multiple packets to be sent before
acknowledgment.
Explanation
Stop-and-wait sends one frame and waits for its ACK. A sliding window allows several frames in flight before acknowledgment, which uses the link better and gives higher throughput.
In which scenario would the ReadConsole system call be used over ReadFile?
AWhen reading input from a network socket
BWhen reading from a database
CWhen reading from the console or terminal window
DWhen reading from a disk file
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Correct answer: (C) When reading from the console or terminal window
Explanation
In the Windows API, ReadConsole reads characters from the console input buffer (the terminal window). ReadFile is the general call for files, pipes and devices.
ENUM is a MySQL-specific type and is not in the SQL:1999 standard, which has DATE, BOOLEAN, CHAR and VARCHAR. Strictly, STRING is not a standard SQL type either.
TCP is full-duplex: once connected, data can flow in both directions at the same time. TCP is connection-oriented and stateful, and does not broadcast.
Consider the following statements.
P. The output of the four inputs AND gate is 1 when all the four inputs values are 1’s.
Q. The output of the four inputs AND gate is 0 when at least one input value is 0.
R. Three AND gates are used in the implement given three variable Boolean function F (A, B,
C) = AB +BC +AC using basic logic gates.
Which of the given statements are correct in a digital logic system?
AOnly P and Q
BP, Q, and R
COnly Q and R
DOnly P and R
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Correct answer: (B) P, Q, and R
Explanation
P and Q describe the AND gate correctly. For AB + BC + AC you need three AND gates (AB, BC, AC) plus OR gates, so R is also true.
Which of the following systems typically DO NOT use contiguous allocation?
ACD-ROM systems
BVideo streaming systems
CGeneral-purpose operating systems with dynamic file sizes
DReal-time systems
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Correct answer: (C) General-purpose operating systems with dynamic file sizes
Explanation
General-purpose OSs have files that grow and shrink, which causes external fragmentation with contiguous allocation. So they use linked or indexed allocation instead.
Contiguous allocation is most suitable for which type of systems?
ASystems with dynamic file sizes
BMulti-user systems with high I/O demands
CReal-time systems requiring fast access
DSystems with limited storage
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Correct answer: (C) Real-time systems requiring fast access
Explanation
Contiguous allocation stores a file in consecutive blocks, which gives fast sequential and direct access. This suits real-time systems, and also read-only media such as CD-ROMs.
What will be the output of the following code?
#include <stdio.h>
int main() {
int arr[] = {1, 2, 3, 4, 5};
printf("%d %d \n", arr[2], *(arr + 2));
return 0;
}
A3 3
B2 2
CCompilation Error
DUndefined Behavior
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Correct answer: (A) 3 3
Explanation
arr[2] and *(arr + 2) both mean the third element, 3, so "3 3" is printed.
What is the output of the following code? #include <stdio.h>
void func(int *p) {
int q = 10;
p = &q;
}
int main() {
int x = 20, *ptr = &x;
func(ptr);
printf("%d\n", *ptr);
return 0;
}
ACompile time error
B20
C10
DGarbage value
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Correct answer: (B) 20
Explanation
C passes the pointer by value, so p = &q changes only the local copy in func. ptr still points to x, and 20 is printed.
A company wants to develop a software tool that identifies duplicate entries in a large
database while ensuring scalability and accuracy. Which computational thinking steps should
be prioritised, and in what order, to achieve an efficient solution?
For this task the key's order is abstraction first: keep only the important features of an entry. Then decompose the task, recognise duplicate patterns, and finally design the algorithm.
When solving a Sudoku puzzle using computational thinking, which step is the most critical
for ensuring efficiency?
AProblem decomposition
BAbstraction
CBrute force approach
DPattern recognition
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Correct answer: (D) Pattern recognition
Explanation
Sudoku is solved efficiently by recognising patterns, such as which numbers are missing in rows, columns and boxes. This cuts down the possibilities far more than brute force.
Which among the following is the primary purpose of using interfaces in Java?
ATo avoid creating objects
BTo achieve multiple inheritance
CTo improve user experience
DTo reduce memory usage
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Correct answer: (B) To achieve multiple inheritance
Explanation
A Java class can extend only one class but can implement many interfaces. Interfaces are therefore Java's way of achieving multiple inheritance of type.
What will be the output of the following code?
class Test {
Test(int x) {
System.out.println("Parameterized Constructor");
}
Test() {
this(10);
System.out.println("Default Constructor");
}
public static void main(String[] args) {
Test obj = new Test();
}
}
AParameterized Constructor followed by Default Constructor
BCompilation Error
CDefault Constructor
DParameterized Constructor
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Correct answer: (A) Parameterized Constructor followed by Default Constructor
Explanation
new Test() calls the no-argument constructor. Its first statement, this(10), runs the parameterized constructor first, so "Parameterized Constructor" is printed and then "Default Constructor".
A 2D array can be initialised with a flat list when both sizes are given: {1,2,3,4} fills row by row. [2,2] is not C syntax, and only the first dimension may be left empty.
Given a 3-dimensional array C[3][4][5] stored in row-major order, with each element
occupying 1 byte, and the base address 3000, what is the address of C[2][3][4]?
A3057
B3059
C3124
D3171
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Correct answer: (B) 3059
Explanation
Offset = i × (4 × 5) + j × 5 + k = 2 × 20 + 3 × 5 + 4 = 59, so the address is 3000 + 59 = 3059.
Consider the following statements regarding digital logic systems and and select the correct
statements.
P. The output of the n inputs NAND gate is 0 when all the n inputs values are 1’s.
Q. The output of the n inputs NAND gate is 1 when all the n inputs values are 0’s.
R. The output of the n inputs NAND gate is 1 when all the n inputs values are 1’s.
S. Minimum three NAND gates are used to implement the given three variable Boolean
function F (A, B, C) = AB +BC using only NAND logic gates.
AOnly P, Q and S
BOnly P, R and S
CP, Q, R and S
DOnly P, Q and R
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Correct answer: (A) Only P, Q and S
Explanation
A NAND gate gives 0 only when all inputs are 1, so P and Q are true and R is false. AB + BC = ((AB)'·(BC)')' needs three NAND gates, so S is true.
Correct answer: (D) A base condition and a recursive call
Explanation
A recursive function needs a base condition to stop and a recursive call that moves toward that base case. Without a base case the recursion never ends.
What will be the output of the following code?
public class ExceptionDemo {
public static void main(String[] args) {
try {
int[] numbers = {1, 2, 3};
System.out.println(numbers[5]);
} catch (Exception e) {
System.out.println("Exception caught: " + e.getClass().getName());
} finally {
System.out.println("Execution completed.");
}
}
}
numbers[5] is past the end of the array, so an ArrayIndexOutOfBoundsException is thrown. getClass().getName() gives its full name, and finally always runs.
Suppose there are n elements in an array A[ ]. If we want to insert a new element at position i in array A[ ], 1 ≤ i ≤ n, causing elements numbered i, i+1, …, n to become numbered:
Ai−1, i, i+1, i+2, i+3, …, n+1
Bi+1, i+2, i+3, …, n+1
Ci−1, i+1, i+2, i+3, …, n+1
Di+2, i+3, …, n+1
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Correct answer: (B) i+1, i+2, i+3, …, n+1
Explanation
To insert at position i, elements i to n each move one place to the right, so they become i+1, i+2, ..., n+1.
If the recursive approach of linear search is used to search a key in a linked list of n elements, then what are the time and space complexity to search an element in a linked list?
ATime Complexity = O(n), Space Complexity = O(1)
BTime Complexity = O(1), Space Complexity = O(1)
CTime Complexity = O(1), Space Complexity = O(n)
DTime Complexity = O(n), Space Complexity = O(n)
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Correct answer: (D) Time Complexity = O(n), Space Complexity = O(n)
Explanation
Recursive search makes up to n calls, so the time is O(n). Each pending call uses a stack frame, so the space is also O(n).
What is the output of the following JavaScript code?
const obj = { name: "Alice" };
Object.defineProperty(obj, "age",
{
value: 25,
writable: false
});
obj.age = 30;
console.log(obj.age);
Aundefined
BError: Cannot modify property
C25
D30
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Correct answer: (C) 25
Explanation
writable: false makes the age property read-only. In non-strict mode, obj.age = 30 is silently ignored, so 25 is printed. Strict mode would throw a TypeError.
A sorting algorithm in which the two or more elements with equal key values appear in the
same order in sorted output as they appear in the input data set is known as a/an:
Ainternal sorting algorithm
Bexternal sorting algorithm
Cstable sorting algorithm
Dunstable sorting algorithm
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Correct answer: (C) stable sorting algorithm
Explanation
A stable sort keeps records with equal keys in their original relative order. Insertion sort and merge sort are stable.
Consider the pseudocode of the function given below.
abc(int n)
{
int i, j, k = 0;
for (i = n/2; i <= n; i++)
for (j = 2; j <= n; j = j * 2)
k = k + n/2;
return k;
}
what will the time complexity of the function abc() be?
AO(n²)
BO(n)
CO(n log n)
DO(log n)
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Correct answer: (C) O(n log n)
Explanation
The outer loop runs about n/2 times, and the inner loop doubles j, so it runs about log₂ n times. That gives O(n log n).
Which of the following is an advantage of the linked list over an array?
ALinked list takes less storage to store the n elements as compared to array.
BLinked list takes less time to access the ith element as compared to array.
CInserting an element at beginning of the linked list takes less time as compared to
array.
DInserting an element as last element of the linked list takes less time as compared to
array.
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Correct answer: (C) Inserting an element at beginning of the linked list takes less time as compared to
array.
Explanation
Inserting at the beginning of a linked list only changes the head pointer, which is O(1). An array must shift every element, which is O(n). Array access by index is faster.
Consider the expression given below:
x = a + b * (c − d) / e + f % g;
The variables have the following values:
a = 8, b = 5, c = 10, d = 3, e = 2, f = 7, g = 3;
If the variables x, a, b, c, d, e, f, g are of integer data type, then what will be the value of x after evaluating the above expression?
A24
B26
C20
D21
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Correct answer: (B) 26
Explanation
b * (c − d) = 5 × 7 = 35, and 35 / 2 = 17 in integer division. f % g = 7 % 3 = 1. So x = 8 + 17 + 1 = 26.
How does one prevent a form from submitting when using JavaScript?
Aevent.preventDefault()
Bform.submit()
Creturn false;
Devent.stopPropagation()
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Correct answer: (A) event.preventDefault()
Explanation
Calling event.preventDefault() in the submit handler cancels the browser's default action, the form submission. stopPropagation() only stops the event from bubbling.
Which of the following library file functions in C program is/are correct?
fwrite()- This function is used for writing an entire block to a given file.
fseek()- This function is used for setting the file position pointer at the specified byte.
ftell()- This function is used to move the file position pointer to the beginning of the file.
Afwrite(), ftell()
Bfwrite(), fseek()
Cfseek(), ftell()
Dfwrite(), fseek(), ftell()
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Correct answer: (B) fwrite(), fseek()
Explanation
fwrite() writes a block of data, and fseek() sets the file position pointer. ftell() only returns the current position; rewind() is the function that moves to the beginning.
Study the given table and calculate the total Trial Balance amount.
Particulars | Amount (₹)
Cash | 54,750.00
Capital | 60,000.00
Purchases | 62,000.00
Sales | 42,250.00
Sales return | 1,600.00
Purchase returns | 1,300.00
Mr. X (Creditor) | 39,800.00
Mr. Y (Debtor) | 21,500.00
Mr. Z (Creditor) | 4,000.00
Furniture | 3,000.00
Wages and Salaries | 5,200.00
Commission received | 700.00
A₹1,15,070
B₹1,48,050
C₹1,25,000
D₹1,51,050
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Correct answer: (B) ₹1,48,050
Explanation
Debits: cash 54,750 + purchases 62,000 + sales return 1,600 + Y 21,500 + furniture 3,000 + wages 5,200 = 1,48,050. The credits also total 1,48,050.
Given the following information of ABC Ltd. for the financial year 2024-25, calculate the total amount of credit sales for the year 2024-25.
Particulars | Amount (₹)
Opening Balance of Sundry Debtors | 50,000.00
Closing Balance of Sundry Debtors | 60,000.00
Cash Collected from Debtors | 6,00,000.00
Discount allowed to Debtors | 10,000.00
On 31st May 2024, the cash balance of AQ Ltd. is ₹5,50,000. The cash receipts and cash
payments during the month of June 2024 aggregated to ₹5,25,000 and ₹4,50,000,
respectively. The rent and salaries yet to be paid amounted to ₹25,000 and ₹36,000,
respectively. Calculate the amount of cash balance as on 30th June 2024 in the books of AQ
ltd.
A₹5,64,000
B₹6,86,000
C₹4,75,000
D₹6,25,000
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Correct answer: (D) ₹6,25,000
Explanation
Closing cash = 5,50,000 + 5,25,000 − 4,50,000 = ₹6,25,000. Unpaid rent and salaries are outstanding expenses and do not reduce the cash balance.
The order and degree of the differential equation (1 + dy/dx + cos(d²y/dx²))^(3/4) = d³y/dx³ is __________.
A3 and 1
B4 and 3
C3 and 4
D3 and 3
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Correct answer: (C) 3 and 4
Explanation
The highest derivative is d³y/dx³, so the order is 3. The key gets degree 4 by raising both sides to the 4th power. Strictly, the cos(d²y/dx²) term means the degree is not defined.
Which of the following is NOT true about a Histogram?
ARectangles have bases on vertical axis.
BIt consists of a set of rectangles.
CAreas of the rectangles are proportional to class frequencies
DThese rectangles represent the range of the data
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Correct answer: (A) Rectangles have bases on vertical axis.
Explanation
Statement A is false: the bases of a histogram's rectangles lie on the horizontal (x) axis, which shows the class intervals. Frequencies are on the vertical axis.
What is a key difference between system software and application software?
ASystem software includes programs like web browsers, while application software
includes operating systems.
BSystem software is designed for end-users, while application software is designed for
system administrators only.
CSystem software operates the computer hardware, whereas application software is
designed to perform specific user-oriented tasks.
DSystem software is optional for computer operation, while application software is
mandatory.
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Correct answer: (C) System software operates the computer hardware, whereas application software is
designed to perform specific user-oriented tasks.
Explanation
System software (OS, drivers, utilities) runs and manages the hardware. Application software (word processors, browsers) does specific tasks for users.
Which programme suggested textbook revision and gender sensitisation of educational
staff?
ANational Digital Literacy Mission
BProgramme of Action (POA) under NPE
CSarva Shiksha Abhiyan
DNational Education Mission
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Correct answer: (B) Programme of Action (POA) under NPE
Explanation
The Programme of Action (1992) under NPE 1986 asked for textbooks to be revised to remove gender bias and for teachers and staff to receive gender-sensitisation training.
Which of the following best exemplifies the 'Integrated' principle in curriculum development
for children with mental retardation?
ATeaching mathematical operations in isolation without real-life application
BEmphasising rote memorisation of isolated facts
CPreparing students for competitive exams
DOrganising activities that combine language, art, and daily living skills
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Correct answer: (D) Organising activities that combine language, art, and daily living skills
Explanation
The integrated principle links learning areas into meaningful activities, for example combining language, art and daily living skills, instead of teaching isolated facts.
Which of the following minimally influences individual differences in personality?
AGenetic predisposition
BSchool infrastructure
CParenting style
DSocioeconomic status
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Correct answer: (B) School infrastructure
Explanation
Personality differences come mainly from heredity and from family and social environment such as parenting and socioeconomic status. School infrastructure has the least influence.