UPPSC Prelims 2004 Science and Technology Questions with Solutions

Explanation

Ray Tomlinson is widely recognized as the father of electronic mail for his pioneering work in 1971 while working at Bolt, Beranek and Newman (BBN). He developed the first system capable of sending mail between users on different hosts connected to the ARPANET, which was the precursor to the modern internet. Tomlinson’s most enduring contribution was the selection of the @ symbol to separate the user’s name from the machine’s name, a convention that remains the global standard today. Prior to his invention, messages could only be sent to others using the same computer. His integration of the SNDMSG and CPYNET programs allowed for the seamless transfer of personal messages across a network of geographically separated computers.

Explanation

The coding scheme uses a positional shift of +2 for each letter in the word to generate the code. In the example provided, the word VARANSI is converted to XCTCPUK by shifting each letter forward by two places in the English alphabet: V → X, A → C, R → T, A → C, N → P, S → U, I → K. To identify the word for which NWEMPQY is the code, the reverse operation of a -2 shift must be applied to each letter. Performing this backward shift gives N-2=L, W-2=U, E-2=C, M-2=K, P-2=N, Q-2=O, Y-2=W. The resulting letters form the word LUCKNOW.

Explanation

The series follows a systematic arithmetic progression for each letter position within the triplets:

First letter: The sequence is C, F, I, L. The letters increase by 3 positions in the alphabet. 3 (C) + 3 = 6 (F) 6 (F) + 3 = 9 (I) 9 (I) + 3 = 12 (L) 12 (L) + 3 = 15 (O)

Third letter: The sequence is H, M, R, W. The letters increase by 5 positions. 8 (H) + 5 = 13 (M) 13 (M) + 5 = 18 (R) 18 (R) + 5 = 23 (W) 23 (W) + 5 = 28 ≡ 2 (B)

Second letter: The sequence follows a +4 increment. 5 (E) + 4 = 9 (I) 9 (I) + 4 = 13 (M) 13 (M) + 4 = 17 (Q) 17 (Q) + 4 = 21 (U)

By identifying the first letter (O) and the last letter (B), the correct term is determined to be OUB.

Explanation

The coding follows a direct letter-to-digit mapping based on the given examples. From DHAKA (42151), we identify D = 4, H = 2, A = 1, and K = 5. From BELLUR (367789), we identify B = 3, E = 6, L = 7, U = 8, and R = 9. Applying these specific values to the word ALLAHABAD, we substitute each letter with its corresponding digit: A becomes 1, L becomes 7, L becomes 7, A becomes 1, H becomes 2, A becomes 1, B becomes 3, A becomes 1, and D becomes 4. This sequential substitution results in the numeric string 177121314.

Explanation

The conversion between metric and imperial units relies on standardized definitions and mathematical ratios. For length, the international foot is defined as exactly 0.3048 meters. Consequently, the reciprocal value for 1 meter is approximately 3.28084 feet, which is commonly rounded to 3.28. For land area, 1 hectare is defined as 10,000 square meters, while 1 acre (referred to as Area in the context of the question) is approximately 4046.856 square meters. This relationship dictates that 1 acre is approximately 0.404686 hectares, rounded to 0.405, and 1 hectare contains approximately 2.47105 acres, rounded to 2.47. All four statements provided represent these standard unit relationships accurately.

Explanation

Geometric correspondence defines a relationship where points and lines in one figure are mapped to specific points and lines in another based on a transformation. While corresponding triangles are often analogues, meaning they maintain structural proportionality or similarity, they are not required to be congruent. Equality of area is a specific condition that only occurs in isometric transformations such as rotation, translation, or reflection. In general interpretations of geometric mapping and projection theory, the scale of the figures often changes, meaning the areas will differ. Therefore, the claim that the areas of corresponding triangles are equal is an incorrect generalization and does not serve as a valid elucidation of the principle of correspondence.

Explanation

The given series is composed of two interleaved arithmetic progressions. The first progression, occupying the odd positions (1st, 3rd, 5th, and 7th), consists of the numbers 5, 9, 13, and Y. The common difference in this sub-series is +4, determined by the operations 5 + 4 = 9 and 9 + 4 = 13. Extending this pattern to find the next term in the sequence yields Y = 13 + 4 = 17.

The second progression, occupying the even positions (2nd, 4th, and 6th), consists of the numbers 15, 12, and X. The common difference in this sub-series is -3, as seen in the transition 15 - 3 = 12. Applying this constant difference to find the next term in the sequence yields X = 12 - 3 = 9. As a result, the hidden values for X and Y are 9 and 17 respectively.