Computer Science Previous Year Questions (page 47)

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DFS goes as deep as possible along one branch before backtracking (using a stack). BFS visits all vertices at the current level before the next level (using a queue).

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Medium-scale integration (MSI) puts a moderate number of gates (roughly tens to a few hundred) on one chip, between SSI and LSI.

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Row, column, square, null and diagonal are standard types of matrix. There is no "case matrix", so i, ii, iii, iv and v are correct.

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An encoder's output depends only on its present inputs, so it is a combinational circuit. Counters and shift registers have memory, which makes them sequential.

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The principle of work and energy states that a body's kinetic energy in state 1 plus the work done on it equals its kinetic energy in state 2 (T1 + ΣU1→2 = T2).

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A join combines rows from several tables on a related (common) column. A subquery is a query nested inside another query, often used to filter on a condition.

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Symmetric encryption, such as AES, uses one shared key to both encrypt and decrypt. Asymmetric encryption, such as RSA, uses a public key and a private key.

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A Monte Carlo algorithm has a fixed (polynomial) running time but may give a wrong answer with small probability. A Las Vegas algorithm is always correct, but its running time varies.

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The CIA triad of Confidentiality, Integrity and Availability makes up the three basic goals of information security.

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For an r × s table, the contingency coefficient C has a maximum of √((k − 1)/k), where k = min(r, s). With rows as the smaller dimension this is √((r − 1)/r).

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TTL is decremented at each router, and the datagram is discarded when it reaches 0. This stops packets from looping forever.

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Coda, developed at Carnegie Mellon, is a distributed file system descended from the Andrew File System (AFS). It adds support for disconnected operation.

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The JDBC type REAL is a single-precision floating-point number with 7 digits of mantissa (Java float). FLOAT and DOUBLE are double precision with 15 digits.

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n = 77 and φ(n) = 6 × 10 = 60. e must satisfy e × 37 ≡ 1 (mod 60). Since 13 × 37 = 481 = 8 × 60 + 1, e = 13.

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Interpolation is a method of estimating unknown values that lie between known data points.

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B-tree indexes keep keys in sorted, hierarchical order, so they handle range queries well. Hash indexes use a hash function, which is good for exact-match lookups but not ranges.

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The balance sheet shows a firm's assets, liabilities and owner's equity at a given date (Assets = Liabilities + Equity).

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end, abort, create (and terminate, wait) are process control system calls. They create, end and manage processes.

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All three are correct points from the scope of business economics: demand forecasting predicts future demand, high inventory ties up funds, and pricing decisions decide profit.

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Dictionary<TKey,TValue> is a .NET collection of key-value pairs, where values are looked up by a unique key.

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Virtual memory uses disk space as a temporary extension of RAM. This lets programs larger than physical memory run, with pages swapped in and out as needed.

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A multiple of both 3 and 4 is a multiple of 12. From 1 to 50 these are 12, 24, 36 and 48, so P = 4/50 = 2/25.

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Inheritance lets a subclass reuse the fields and methods of an existing class, so its main purpose is code reusability.

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A foreign key is a column in one table that refers to the primary key of another table.

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A plotter produces drawings on paper, so it is an output device. A scanner, a game controller and a digitiser are input devices.

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Per the key, a database, MIS executives and control and maintenance of the MIS are the core prerequisites of a good MIS, while staff support is not counted as one.

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An RDBMS stores data in tables (relations) made of rows and columns, and uses keys to relate the tables.

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prompt() shows a dialog box with a text field and returns what the user types. alert() only displays a message.

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ADO.NET's listed features are interoperability, scalability, maintainability, programmability and performance. "Reachability" is not one of them.

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EPS = profit for equity shareholders ÷ number of equity shares = 10,00,000 ÷ 20,000 = ₹50.

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The shift operator satisfies Ef(x) = f(x + h), and Δf(x) = f(x + h) − f(x) = (E − 1)f(x). So Δ = E − 1, which means E = 1 + Δ.

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Having no universal standard for quality and reliability is a limitation of e-commerce, not an advantage.

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Pseudocode is already close to the structure of a programming language, so it is the easiest form to turn into actual code.

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A CSS pre-processor such as Sass or LESS adds variables, nesting, mixins and functions to CSS. It simplifies and extends CSS, then compiles to plain CSS.

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A zombie process has finished executing, but its entry stays in the process table until the parent reads its exit status with wait().

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E-commerce supports several business functions, including marketing, finance (online payments) and supply chain management.

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ICMP is used for error reporting and diagnostics, such as "destination unreachable" and "time exceeded", and by ping and traceroute.

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Signature-based detection matches traffic against a database of known attack patterns. It is the most widely used method of intrusion detection.

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CSS Grid is a two-dimensional layout system (rows and columns). Flexbox is one-dimensional, arranging items along a single row or column.

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fork() returns −1 if creating the child fails. It returns 0 in the child, and the child's PID in the parent.

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Tokens such as keywords, identifiers, constants, strings, operators and punctuators are the smallest individual units of a C program and the basic elements the compiler recognises.

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A static array's size is fixed at compile time. A dynamic array (created with malloc or realloc) can be resized at runtime.

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A design pattern (such as Singleton or Observer) is a reusable, standard solution to a common software design problem.

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IPSec works in transport mode, which protects only the payload, and tunnel mode, which encapsulates and protects the entire IP packet.

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Virtual memory combines RAM with space on the hard disk (swap/page file). Data in use is kept in RAM, and the rest is paged out to disk.

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Incremental revenue is the extra revenue that comes from a specific action, such as launching new products or entering new markets.

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Cellular networks are of two basic kinds: circuit-switched (e.g. GSM voice) and packet-switched (e.g. GPRS, LTE data).

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A software patch is an update that fixes bugs or security vulnerabilities in an existing program.