Computer Science Previous Year Questions (page 49)

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Interpolation estimates values between known data points by fitting a curve (curve fitting) or a straight line (linear analysis) through the given data.

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To communicate over the Internet, a computer needs a Network Interface Card (the hardware connection) and the TCP/IP protocol suite (rules for addressing and transmitting data). The other items are peripherals.

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Pierre-Simon Laplace gave the classical definition of probability: the ratio of favourable outcomes to the total number of equally likely outcomes.

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The profit and loss account records indirect expenses and incomes and shows the net profit or loss. The trading account gives only gross profit, and the balance sheet shows financial position.

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Application programs talk to database servers through standard database APIs: ODBC (Open Database Connectivity) or JDBC for Java. These drivers send SQL queries and return results.

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Merge sort uses divide and conquer: it splits the array into halves, sorts each half recursively and then merges the two sorted halves.

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In Linux, the rm command deletes files (rm file.txt). rmdir removes only empty directories, and 'delete' and 'rdir' are not standard Linux commands.

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The Poisson distribution is a discrete distribution (given by a probability mass function) for counting events. Gaussian and Rayleigh are continuous distributions, and the CDF is not a density.

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Gaussian process regression (kriging) is a non-linear interpolation method from probability and statistics. It treats the unknown function as a random process and predicts values between data points.

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fork() splits a process into concurrent parts, and join() waits for them to finish and recombine. Together they form a complete concurrent subroutine; sleep() only suspends execution.

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∇f = (3x² + 3yz, 3y² + 3xz, 3xy). At (1, 2, −1) this is (−3, 9, 6) = 3(−1, 3, 2). Its magnitude is 3√14, so the unit normal is (−î + 3ĵ + 2k̂)/√14.

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Error control and flow control between adjacent nodes are data link layer functions, and end-to-end versions belong to the transport layer. Routing and congestion control are network layer functions.

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scanf() and printf() are standard input/output functions declared in stdio.h.

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Under the Companies Act, 2013, a public company needs at least 7 members, while a private company needs at least 2.

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A software package is a set of related programs supplied together with the necessary documentation, such as manuals and guides, for a particular task.

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An IPv4 address (4 bytes) has two parts: a network address that identifies the network and a host address that identifies the device on it. Port and MAC addresses belong to other layers.

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A session key is a temporary symmetric key generated for one communication session. It is used to encrypt the data exchanged between the end systems and is then discarded.

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A bus is a set of parallel wires (lines) that carry data, address and control signals between computer components at the same time.

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Polarisation is possible only for transverse waves, because their vibrations are perpendicular to the direction of travel and so can be restricted to one direction. Longitudinal waves cannot be polarised.

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A company is a separate legal entity, so the liability of its members (shareholders) is limited to the unpaid amount on their shares. Sole proprietors and ordinary partners have unlimited liability.

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Authentication is the process of verifying a user's claimed identity, for example with passwords, OTPs or biometrics. Integrity and confidentiality are about protecting the data itself.

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Joel Dean's methods for forecasting demand for new products include the evolutionary, substitute, growth curve, opinion polling, sales experience and vicarious approaches. All three listed are valid methods.

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Web browsers act as a universal client (front end) for web-based database applications. They send requests over the Internet to the web or application server that connects to the back-end database.

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In Linux, directories are removed with rm -r (recursive), or with rmdir for empty ones. 'Delete' and 'Erase' are not Linux commands, so rm is the answer.

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Merge sort always halves the array (log n levels) and does O(n) merging work at each level. So its best, average and worst case are all O(n log n).

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Encryption converts readable plain text into unreadable cipher text using a key. Plain text is the information that gets transformed; cipher text is the result.

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Virtual reality systems use interactive graphics hardware and software to create computer-generated simulated environments that mimic real-world activities, such as flight simulators.

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Good software design aims for low coupling (little dependency between components) and high cohesion (elements inside a component strongly related), which makes systems easier to maintain and reuse.

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Fixed assets (non-current assets such as land, buildings and machinery) are held for long-term use, more than one year, in the business rather than for resale.

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Magnetic tape allows only sequential access: to reach a record, the tape must wind past everything before it. Hard disks, CDs and DVDs allow direct (random) access.

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The ability to take many forms is polymorphism. Operator overloading is a form of compile-time polymorphism, where one operator behaves differently for different types, which is why it is the keyed option.

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Dividing by 2 is done by shifting the register one bit to the right: 10100 becomes 01010 (20 ÷ 2 = 10).

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A socket is one endpoint of a two-way inter-process communication link, identified by an IP address and port number. Two processes communicate through a pair of sockets.

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Protected members are accessible inside the class and in classes derived from it, but not to unrelated outside code. Private members are not accessible in derived classes.

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The accumulator's size equals the processor's word length. For a 32-bit processor it is 32 bits = 4 bytes.

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The .NET Hashtable class stores key/value pairs and lets each element be accessed by its unique key using hashing. ArrayList and linked lists are accessed by index or position.

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System software, such as the operating system, provides the instructions that control and manage the computer's basic operations and hardware.