Computer Science Previous Year Questions (page 14)

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History includes economic, political and other histories, so social science subjects are interdisciplinary and interrelated, not independent.

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Debates and discussions on social issues, and teaching students to cooperate, both make social science learning participatory.

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A scientific argument links a hypothesis, the predictions drawn from it, and the evidence that tests those predictions.

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Empiricism holds that knowledge comes from sensory experience and evidence. Scepticism is doubt about claims to knowledge.

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The NCERT EVS syllabus for classes III-V uses six themes: Family and Friends, Food, Shelter, Water, Travel, and Things We Make and Do. So all three are themes.

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Both are specific, measurable application-level objectives that link mathematics to daily life, so both are instructional objectives.

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Every row of the second matrix is 2 times the corresponding row of the first. Multiplying all three rows of a 3×3 matrix by 2 multiplies the determinant by 2³ = 8, so the new determinant is 8 × (−p) = −8p.

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byx = (nΣxy − ΣxΣy) / (nΣy² − (Σy)²) = (5×41 − 12×12) / (5×45 − 144) = (205 − 144) / (225 − 144) = 61/81. Since Σx² = Σy², both denominators give the same value.

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The chance that all four shots miss is 0.4 × 0.5 × 0.6 × 0.8 = 0.096. So P(at least one hit) = 1 − 0.096 = 0.904.

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Under the Companies Act, a public limited company needs at least 7 members (shareholders). A private company needs only 2.

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Ctrl + H opens the Find and Replace dialog in MS Word. Ctrl + R right-aligns text, Ctrl + D opens the Font dialog and Ctrl + A selects all.

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FORTRAN stands for FORmula TRANslation. It was developed by IBM in the 1950s for scientific and mathematical computing.

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The kernel is the core of the OS. It stays resident in main memory and manages the CPU, memory and devices. Other OS parts can be loaded only when needed.

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Perl is a scripting language that is normally interpreted. C is a compiled language: source code is turned into machine code before it runs.

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The three pillars of object-oriented programming are encapsulation, inheritance and polymorphism, so a language must support all three.

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Rows run from −4 to 1, which is 1 − (−4) + 1 = 6 rows. Columns run from 6 to 10, which is 10 − 6 + 1 = 5 columns. Total elements = 6 × 5 = 30.

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A stack holds pending work in LIFO order. The postponed items wait on the stack and are processed only after the current conditions are met, as in recursion or backtracking.

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Quick sort's worst case happens when the pivot is always the smallest or largest element, for example on already sorted input. Each partition then removes only one element, giving Θ(n²).

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Polish notation is prefix notation. (A*B + C) becomes +*ABC and (E − F*G) becomes −E*FG. Dividing the first by the second gives /+*ABC−E*FG.

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++v makes v = 9 before the division. Then i = 8/9 = 0 because integer division drops the fraction. printf prints 0 (followed by the literal text "/n").

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This new-order is right, node, left, which is reverse in-order. The right subtree of P gives Z, V, Y, X, W. Then comes P. The left subtree gives S, U, T, Q, R.

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14 has two children, so it is replaced by its in-order successor 16, the smallest key in its right subtree. 16's right child 20 moves up. Pre-order is then 16, 10, 7, 13, 11, 20, 18, 25, 22.

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short a[5] takes 5 × 2 = 10 bytes. The union takes the size of its largest member, long, which is 8 bytes. Total = 10 + 8 = 18 bytes, ignoring alignment padding.

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XMODEM is a simple file-transfer protocol for uploading and downloading files between computers over modems. It sends data in 128-byte blocks with a checksum.

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A network operating system, such as Windows Server or Novell NetWare, lets computers on a network share files, printers and other resources.

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In half duplex, data can travel in both directions but only one way at a time, like a walkie-talkie. Full duplex allows both directions at once, and simplex allows only one direction.

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An OMR (Optical Mark Reader) senses marks shaded in fixed positions, so it is used to read answers on objective tests and survey forms.

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A dot-matrix printer forms characters by pins striking an inked ribbon against the paper, so it is an impact printer. Inkjet, laser and thermal printers are non-impact printers.

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Magnetic tape is a sequential-access device, not a direct-access one, so statement I is false. It does store large volumes of data cheaply and is widely used for backup.

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The light is on only when the two inputs differ, which is exactly the XOR truth table: 0,0→0; 1,1→0; 0,1 or 1,0→1.

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A twisted ring counter, also called a Johnson counter, feeds the complement of the last flip-flop's output back to the D input of the first stage. An n-bit Johnson counter has 2n states.

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For a DAC, linearity error is the largest deviation of the output from the ideal straight line. It is expressed as a percentage of the full-scale, or maximum, output voltage.

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In Gray code, consecutive numbers differ in exactly one bit, for example 01 → 11 → 10. This is useful in shaft encoders and K-maps.

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In signed number representation, the most significant bit is the sign bit: 0 means positive and 1 means negative. Both pairs are correct.

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(21121)₃ = 2×81 + 1×27 + 1×9 + 2×3 + 1 = 205. Converting to base 4: 205 = 3×64 + 0×16 + 3×4 + 1, so the value is (3031)₄.

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Information processing covers acquiring, storing, organizing, retrieving, displaying and disseminating information.

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Cardinality is the number of tuples (rows) in a relation, so it is 500. The number of attributes (50) is the degree.

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E.F. Codd gave 12 rules, numbered 1-12 with an extra Rule 0 (the foundation rule), that a DBMS must satisfy to be called fully relational.

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Fan traps and chasm traps are the two kinds of connection trap in ER modelling. A fan trap gives ambiguous paths between entities, and a chasm trap gives a missing path.

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In crow's-foot notation, a single bar means "one". A line with a single bar marks a one-to-one link. A crow's foot means "many", and a circle means "zero" (optional).

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The recognised database design approaches are top-down, bottom-up, inside-out and mixed. There is no "up-down" approach.

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COUNT is an aggregate function: it returns one value computed over a set of rows. MINUS, INTERSECT and UNION are set operators.

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64K = 2¹⁶ words, so 16 address lines are needed. Each word is 8 bits wide, so 8 data lines are needed.

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1010 ⊕ 1100 = 0110, and this result is stored in R1. R2 is only read, so it stays 1100.

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The mask (selective clear) micro-operation ANDs bits with a mask, clearing the bits where the mask has 0. So it is equivalent to an AND gate.

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In indirect addressing, the first memory access reads the operand's effective address and the second fetches the operand itself. That is 2 memory references.

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ADD R1, A, B names three operands, a destination R1 and two sources A and B (R1 ← A + B), so it is a three-address instruction.

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The span attribute of <colgroup> or <col> sets how many columns the group covers. Colspan and rowspan are used on table cells (td or th).

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A bill is dishonoured when the drawee does not pay it on the date of maturity, and it is then recorded as dishonoured in the books.

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Accounting aims to keep a systematic record of business transactions and to find the profit or loss of the business, along with showing its financial position. Both statements are objectives.