BPSC TRE 1.0 (2023) Computer Science Class 11-12 — Previous Year Paper

Explanation

Three-digit multiples of 5 run from 100 to 995: (995 − 100)/5 + 1 = 180.

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The product is (3/2)(4/3)(5/4)…(121/120), which telescopes to 121/2 = 60.5.

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120 km at 90 km/h takes 4/3 h = 1 h 20 min; the remaining 80 km at 40 km/h takes 2 h; total 3 h 20 min.

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Let SP = 100; loss = 10, so CP = 110. Loss on CP = 10/110 × 100 = 100/11 = 9 1/11 %.

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Reading the garbled day-3 figure as 9/16: 2/5 = 0.40, 3/4 = 0.75, 9/16 ≈ 0.56. Starting with the same number each day, day 2 has the largest fraction.

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Carpet length = 810/4.50 = 180 m; area = 180 × 0.75 = 135 m²; breadth = 135/18 = 7.5 m.

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B's one-day work = 1/15 − 1/20 = (4 − 3)/60 = 1/60, so B alone takes 60 days.

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Let the fraction be n/d with n + d = 11. (n + 1)/(d − 2) = 2/3 gives 3n + 3 = 2d − 4. Using d = 11 − n: 5n = 15, so n = 3, d = 8, giving 3/8.

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An isotropic source emits into the full solid angle 4π sr, so flux = 4π × I = 4π × 2 = 8π lumen.

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Fast-moving air over the tube top lowers pressure there (Bernoulli's principle), so the liquid is pushed up and sprayed out.

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Basic lead carbonate, 2PbCO₃·Pb(OH)₂, is called white lead and was used as a white pigment. Red lead is Pb₃O₄ and litharge is PbO.

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Atomic radius decreases across a period as nuclear charge increases, so in Li, Be, B the largest is lithium.

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W. W. Garner and H. A. Allard discovered photoperiodism in 1920 while studying flowering in tobacco (Maryland Mammoth).

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Silent Valley National Park is protected for its rare, undisturbed tropical evergreen rainforest and endangered species such as the lion-tailed macaque.

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At rest (expiration) the diaphragm is dome-shaped or arched; during inspiration it contracts, flattens and is lowered. Normal respiration involves both, so more than one option is correct.

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Lymphocytes (B and T cells) give specific immunity by making antibodies and killing infected cells. Platelets help clotting and RBCs carry oxygen.

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Gyan Deepak was written by Dariya Saheb, an 18th-century saint-poet of Bihar (Dharkandha, Rohtas) who founded the Dariyapanthi sect.

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The UGC launched the UTSAH (Undertaking Transformative Strategies and Actions in Higher Education) portal in 2019 to improve quality in higher education.

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The Dr. A. P. J. Abdul Kalam Students Satellite Launch Vehicle Mission was launched on 19 February 2023 from Pattipulam near Chennai, carrying 150 student-built PICO satellites.

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India's first 99.999% pure green hydrogen plant was commissioned by Oil India Ltd at Jorhat, Assam in April 2022, a city not among the options.

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The UN General Assembly declared 2023 the International Year of Millets, on a proposal by India.

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The 2022 Nobel Peace Prize went to Belarusian activist Ales Bialiatski with the organisations Memorial (Russia) and the Center for Civil Liberties (Ukraine). Nadia Murad won in 2018 and Maria Ressa in 2021.

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As per the official key, retired Justice Sanjay Kumar was appointed Chairman of the Bihar State Commission for Backward Classes in January 2022.

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'Ganga Maiya Tohe Piyari Chadhaibo' (1963), encouraged by Dr. Rajendra Prasad, was the first Bhojpuri film. 'Nadiya Ke Paar' (1982) came much later.

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From east to west: Namrup (Assam), Obra (Sonbhadra, UP), Parichha (Jhansi, UP), Kota (Rajasthan), i.e. 2, 3, 4, 1.

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As per the official key, India's climate under Trewartha's scheme is described as the subtropical monsoon type (humid subtropical with dry winter, Caw, over much of the north).

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According to IMD normal withdrawal dates, the south-west monsoon withdraws from the Hyderabad region around 15 October.

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As per Census 2011, Goa is the most urbanised state, with about 62% urban population, ahead of Maharashtra and Karnataka.

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Malnad is the hilly, heavily forested western part of the Karnataka Plateau along the Western Ghats; the eastern part is the Maidan.

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The Peninsular plateau is a stable block of the ancient Gondwana landmass, which split from Africa, Australia and Antarctica.

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Census 2011: Bihar's population of about 10.4 crore is about 8.58-8.6% of India's 121 crore.

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Vaishali lies north of the Ganga, so Patna–Vaishali is not a south-of-Ganga pair. Patna, Munger, Gaya and Arwal are all south of the river.

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Raja Ram Mohan Roy, founder of the Brahmo Samaj and a pioneer of social reform, is called the 'Prophet of New India' and 'Father of the Indian Renaissance'.

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Bankim Chandra's Anandamath (1882), which contains 'Vande Mataram', is set against the Sannyasi Rebellion in late-18th-century Bengal.

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Vinayak Damodar Savarkar founded Abhinav Bharat (1904) and took it to London while staying at India House.

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The Ghadar Party was founded in 1913 by Indians on the Pacific coast of the USA (San Francisco), led by Lala Har Dayal and Sohan Singh Bhakna.

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The official BPSC key marks None of the above for this question, so none of the listed Munda leaders is accepted as the commander-in-chief appointed by Birsa Munda.

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The Bihar Socialist Party was formed in 1931 by Phulan Prasad Varma, with Jayaprakash Narayan among its leading figures.

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The Bihar Provincial Congress Committee was formed in 1908 with headquarters at Patna, after the first Bihar Provincial Conference held that year.

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Revolutionary Sachindra Nath Sanyal set up a branch of the Anushilan Samiti in Patna in 1913, drawing students mainly from B. N. College.

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Time sharing let many users at remote terminals use one computer interactively at the same time, which is seen as the start of computer communications.

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Pascal was designed by Niklaus Wirth to teach structured programming. It has block structure and control structures, so it is better suited to structured code than FORTRAN or BASIC.

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Browsers display web pages written in HTML (with CSS and JavaScript). None of the options is HTML: machine code, assembly language and C++ are not used to describe web pages.

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All three statements are true: a compiler takes the source program as input, translates the whole of it at once, and produces object code as output.

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Compaction moves the processes in memory so they sit next to each other, which gathers all free memory into one block and removes external fragmentation.

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In most languages, identifiers cannot begin with a digit, so 123Variable is invalid. myVariable and _myVariable are valid.

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This describes the physical organisation of memory: secondary storage keeps programs and data long-term, while main memory holds what is currently in use.

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Turbo C++ reports "Statement missing ;" and modern compilers say "expected ';'". None of the listed messages matches exactly.

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A graphics package is a set of libraries, such as graphics.h, that gives programs functions for drawing 2D graphics.

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In Turbo C++, Ctrl+F9 compiles and runs the program. Alt+F9 only compiles, and Alt+F5 shows the output screen.

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The control unit sends control signals (timing and control pulses) to the ALU, memory and I/O to direct how they work.

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User-defined header files in C++ use the .h extension, for example #include "myfile.h". .cpp is used for source files.

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Direct, indirect and immediate addressing are all commonly used by CPUs, so more than one option applies.

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Deleting a null pointer is a no-op that the C++ standard guarantees to be safe. The code compiles and runs normally.

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Buffer registers temporarily hold data so that fast and slow devices, which transfer data at different speeds, can work together.

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A PCI bus, connected through a bridge, extends the processor bus so that more devices can be attached.

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In memory-mapped I/O, I/O device registers are given addresses in the same address space as memory. The same load and store instructions then access both.

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In ADD X Y the operands are given by their memory addresses X and Y, which is absolute (direct) addressing.

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int array[10]; declares an array of 10 integers by giving the type, the name and the size in square brackets.

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A view is a virtual table, the stored result of a query. It does not hold its own data and is built from the base tables when used.

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A table can have only one primary key, although that key may be made of several columns (a composite key).

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Char arrays cannot be joined with +. s1 + " " tries to add two pointers, which is invalid, and an array cannot be initialised from such an expression, so the code gives a compile error.

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UNION is a set operator that combines the results of queries. PRIMARY KEY and NOT NULL are constraints.

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COUNT, SUM, AVG, MIN and MAX are aggregate functions. COMPUTE is not a standard SQL aggregate function.

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Charles Babbage designed the Difference Engine and the Analytical Engine, so he is called the father of the computer. Gosling created Java and Ritchie created C.

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ORDER BY sorts in ascending (ASC) order by default.

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Besides the condition flags (CF, ZF, SF, OF), the IA-32 EFLAGS register also provides TF (trap), IF (interrupt enable) and IOPL (I/O privilege level), so more than one option is correct.

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HAVING filters groups made by GROUP BY, while WHERE filters individual rows before they are grouped.

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In program-controlled I/O (polling), the CPU keeps checking a device's status flag until the device is ready.

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The WITH clause (a common table expression) defines a temporary named relation that exists only for that query.

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ROUND(65.726, −1) rounds to the nearest ten, because a negative position counts left of the decimal point, so 65.726 becomes 70.

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A matrix is sparse when most of its elements are zero, meaning more than half of the m × n elements.

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COMMIT makes the changes made by a transaction permanent. ROLLBACK undoes them, and TRUNCATE removes all rows from a table.

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Tables can be joined with join operations such as natural join and union join, or by using subqueries, so more than one option applies.

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Array elements are stored next to each other, so any element can be reached directly by its index in O(1) time. Arrays hold only one data type, and indexing starts at 0.

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Recursion uses a stack. Each call pushes an activation record, and the record is popped when the call returns.

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For a + (b*c) + (d*e): bc* is added to a to give abc*+, then de* is added to give abc*+de*+.

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Linear, circular and double-ended queues (deques) are all real types of queue, so none of the options is wrong.

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Before deleting, check for underflow (an empty queue). Overflow is checked before inserting.

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After the steps the deque is: 10; 20 10; 20 10 30; 10 30; 10 30 40; 10 30 40 10; 10 30 40; then 10 30 40 15.

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A deque (double-ended queue) allows insertion and deletion at both the front and the rear.

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With this convention, front and rear start at −1. Front = rear = −1 means the queue is empty, and front = rear ≥ 0 means it holds one element.

Explanation

Binary trees are traversed in preorder, inorder, postorder or level order. Randomized traversal is not a standard binary tree technique.

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A DBMS supports access by many users at once (concurrency control). Single-user-only access is not a DBMS feature.

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A doubly linked list allows traversal in both directions but needs extra space for the previous pointer. It is harder to implement than a singly linked list, not easier.

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Referential integrity requires every foreign key value in the referencing relation to appear as a key value in the referenced relation.

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All three statements are true properties of a binary search tree, so none of them is false.

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Y = AB + BC + AC is a sum (OR) of product (AND) terms, so it is in sum-of-products (SOP) form.

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The canonical forms are sum of minterms (SOM, or canonical SOP) and product of maxterms (POM, or canonical POS).

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The circuit gives A + B from the OR gate, then three AND gates in turn multiply it by C, D and E. So Y = C(A + B)DE, with E not inverted.

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Boolean algebra is used in designing digital computers, in building logic symbols and gates, and in switching circuit theory, so more than one option applies.

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The control unit generates control signals that direct the ALU, memory and I/O units.

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Digital clocks at stations show digits on seven-segment displays, which are driven by seven-segment (BCD-to-7-segment) decoders.

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Optical fiber carries data as light, so it is immune to electromagnetic interference. Twisted pair and coaxial cable carry electrical signals that interference can affect.

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In a star topology every device is connected to a central hub or switch, which controls the communication.

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The World Wide Web is the collection of hypertext documents (web pages) on the Internet that are linked by hyperlinks.

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When an IPv6 header is translated to IPv4, the flow label is ignored. Using it is not part of the procedure, whereas extracting the rightmost 32 bits and dropping the priority are.

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Giving every user full access rights lets anyone change or delete data, which breaks integrity. Locks and anti-theft devices protect the system.

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The MAC sublayer handles functions that depend on the medium, such as framing and access control for Ethernet or Wi-Fi. LLC is independent of the medium.

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Peer-to-peer is a network architecture (model), not a topology. Ring and bus are physical topologies.

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When a mail server sends mail to another mail server, it acts as an SMTP client and the receiving server acts as the SMTP server.

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An IPv6 address is 128 bits long. None of the listed sizes (32, 64, 256) is right; 32 bits is IPv4.

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ios::trunc discards the contents of an existing file when it is opened, cutting its length to zero.

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The TCP/IP host-to-host (transport) layer matches the OSI transport layer and provides TCP and UDP.

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Official BPSC final answer key: (D). Note: by the usual reading only statements 2 and 3 are correct, i.e. option (B).

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Ping (Packet InterNet Groper) uses ICMP echo messages to report packet loss and round-trip time. It does not check ports.

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The function takes a float* and a char** and returns an int**, so the correct declaration is int **fun(float *, char **).

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Each party keeps its own private key secret. In public-key encryption, the receiver decrypts with the private key that only the receiver holds.

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factorial(a + 1) makes the argument grow (3, 4, 5, ...), so a > 1 is never false. The recursion never ends, the stack overflows, and the program crashes with a segmentation fault.

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A pure object-oriented language must support encapsulation, inheritance and polymorphism (along with abstraction and objects), so all three are required.

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Both (B) and (C) are valid: class derived : access base { }; and, without an access specifier, class derived : base { }; where the default is private for classes.

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std::is_array<T> (in <type_traits>) checks whether a given type is an array type, returning true or false.

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A class is a blueprint, and an object is an instance of its class. The reverse statement is wrong.

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A class becomes abstract when it has at least one pure virtual function, for example virtual void f() = 0;. Such a class cannot be instantiated.

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All three statements are true. C++ does static type checking at compile time and dynamic checking with RTTI and dynamic_cast, and member functions can be declared const.

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Data hidden inside the classes shows encapsulation, and topper deriving from student with public shows inheritance. There is no overloading or overriding, so polymorphism is not shown.

Explanation

Computer chips are made mainly from silicon, a semiconductor used for transistors and integrated circuits.