UPSC CBI DSP LDCE

41. A person wishes to apply a formula in the entire column of the spreads

A person wishes to apply a formula in the entire column of the spreadsheet, with regard to only one cell. Which type of referencing should he use to obtain correct result?

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Relative referencing
Hybrid referencing
Hyperlink
Absolute referencing
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The correct answer is D) Absolute referencing.
Absolute referencing in a spreadsheet uses dollar signs ($) before the column letter and row number (e.g., $A$1) to fix the reference to a specific cell. When the formula containing an absolute reference is copied to other cells, the reference remains unchanged, always pointing to the original cell. This is essential when a formula in an entire column needs to refer consistently to a single specific cell.
Relative referencing (e.g., A1) adjusts the cell reference based on the relative position when copied to other cells. Hybrid referencing (e.g., $A1$ or A$1$) fixes either the column or the row, but not both. A hyperlink is a link to another location or document and is unrelated to cell referencing in formulas.

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42. A router works at which layer of Open Systems Interconnection (OSI)

A router works at which layer of Open Systems Interconnection (OSI) model?

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Physical layer
Data link layer
Network layer
Application layer
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The correct answer is C) Network layer.
Routers are network devices that primarily operate at the Network layer (Layer 3) of the OSI model. They use logical addresses (like IP addresses) to determine the best path for forwarding data packets across different networks.
The Physical layer (Layer 1) deals with the physical transmission of data (e.g., cables, connectors, signal voltage). Devices at this layer include hubs and repeaters. The Data Link layer (Layer 2) handles framing and addressing within a local network segment using physical addresses (like MAC addresses). Devices at this layer include switches and bridges. The Application layer (Layer 7) is where network applications reside and interact with the network service.

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43. The process of converting digital signals to analog signals is known

The process of converting digital signals to analog signals is known as

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demodulation
modulation
transmission
conversion
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The correct answer is B) modulation.
Modulation is the process of varying one or more properties of a periodic waveform (the carrier signal) with a modulating signal, which typically contains the information to be transmitted. When transmitting digital data over an analog medium (like telephone lines or radio waves), the digital signal is used to modulate an analog carrier. This process effectively converts the digital information into an analog signal that can be transmitted.
Demodulation is the reverse process, extracting the original information-bearing signal from the modulated carrier, often converting an analog signal back into a digital signal at the receiving end. Transmission is the act of sending signals. Conversion is a general term and not specific to this process in communication systems. In the context of digital communication over analog channels, the conversion of digital signals to analog signals for transmission is achieved through modulation.

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44. Which one among the following is not an audio file format?

Which one among the following is not an audio file format?

WAV
MPEG
WMA
RAW
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An audio file format is a file format for storing digital audio data on a computer system.
Let’s examine the options:
A) WAV (Waveform Audio File Format): A standard digital audio file format used for storing waveform audio data. It is an audio file format.
B) MPEG (Moving Picture Experts Group): MPEG is a standard for digital video and audio compression. While MPEG standards define audio compression formats (like MP3, AAC), and file formats based on these standards (.mp3, .aac, .mp4 which can contain audio), the term “MPEG” itself often refers to the standards or formats that primarily handle video with accompanying audio (like .mpeg or .mpg files). However, given the context of typical audio formats, MPEG is related to audio formats.
C) WMA (Windows Media Audio): An audio data compression technology developed by Microsoft. Files using this technology (e.g., .wma) are audio file formats.
D) RAW: In computing and digital media, “raw” data refers to data that has received minimal processing. While “raw audio” exists (uncompressed PCM), “RAW” as a file format name is most commonly associated with image files produced by digital cameras (like .cr2, .nef, .dng, .arw). It’s not a standard name for an audio file format in the same way WAV or WMA are. Compared to the other options, RAW is the least likely to be considered a standard audio file format.

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Therefore, RAW is the one that is not a standard audio file format.

Audio file formats are specific structures for storing digital sound. WAV and WMA are standard audio formats. MPEG relates to standards that include audio, though specific format names are often used (like MP3). RAW is primarily associated with image formats or unprocessed data, not a standard audio file format name.
Other common audio file formats include MP3, AAC, FLAC, OGG, AIFF, etc. While “raw audio” data exists, it’s generally considered data *before* being put into a standard audio file format container, or it might be saved in simple `.raw` or `.pcm` files without the header information found in formats like WAV.

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45. Which one of the following is not an operating system?

Which one of the following is not an operating system?

Linux
Mac OS
Google Chrome
Windows XP
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An operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. It is the fundamental software that runs on a computer and manages the system’s resources.
Let’s examine the options:
A) Linux: A family of open-source Unix-like operating systems. Examples include Ubuntu, Fedora, Debian, etc. It is an operating system.
B) Mac OS: (Now macOS) The operating system developed by Apple Inc. for its Macintosh computers. It is an operating system.
C) Google Chrome: A free web browser developed by Google. A web browser is an application program that runs on an operating system, not an operating system itself.
D) Windows XP: A version of the Microsoft Windows line of operating systems, released in 2001. It is an operating system.

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Therefore, Google Chrome is not an operating system.

An operating system is the core software that manages computer hardware and provides a platform for running application software. A web browser is an example of application software.
Other common operating systems include Android, iOS, Unix, Chrome OS (which is an operating system, distinct from the Chrome browser). The question asks for which one is *not* an operating system.

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46. Which one of the following is not a function of operating system?

Which one of the following is not a function of operating system?

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Protection and security
Store and handle data
Device management
File management
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An Operating System (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. Key functions of an OS include:
A) Protection and security: Managing user access, permissions, and resource protection. This is a fundamental OS function.
C) Device management: Managing hardware devices through drivers, controlling I/O operations. This is a fundamental OS function.
D) File management: Organizing and managing files and directories on storage devices, providing a file system. This is a fundamental OS function.
B) Store and handle data: While the OS provides the infrastructure (like file systems and memory management) for data to be stored and accessed by applications, the primary function of storing, manipulating, and interpreting the *content* of data belongs to application programs (like databases, word processors, etc.), not the core OS itself. The OS manages *how* data is stored and accessed on physical media, but not the *data itself* in the sense of its content or meaning. Therefore, “Store and handle data” is not typically listed as a distinct primary function of an operating system compared to the others.
Core functions of an operating system include process management, memory management, file management, device management, and protection and security. Storing and handling the *content* of data is primarily the role of application software, facilitated by the OS’s file and storage management capabilities.
The phrase “Store and handle data” could vaguely relate to memory management or storage management, but these are usually described more specifically. Given the standard classification of OS functions, B is the least accurate or least distinct description of a core OS role compared to the other options.

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47. Which one of the following is not a part of program design phase?

Which one of the following is not a part of program design phase?

Algorithm
Pseudocode
Flowchart
Code
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The software development life cycle typically includes phases like Requirements Gathering, Design, Implementation (Coding), Testing, Deployment, and Maintenance.
The program design phase focuses on creating a blueprint for the software system. This involves defining how the program will work logically and structurally before writing the actual code.
– Algorithm: A set of well-defined instructions for solving a problem. Developing algorithms is a key part of the design phase.
– Pseudocode: An informal high-level description of the operating principle of an algorithm. It’s a tool used in design to outline the algorithm’s logic.
– Flowchart: A diagram representing the sequence of operations in an algorithm or process. Flowcharts are used in design to visually represent the program’s logic flow.
– Code: The actual source code written in a programming language (like C++, Java, Python, etc.). Writing code belongs to the Implementation phase, which follows the Design phase.

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Therefore, ‘Code’ is not a part of the program design phase.

The program design phase involves planning the structure and logic of a program using tools like algorithms, pseudocode, and flowcharts. Coding is the subsequent phase where the design is translated into a specific programming language.
Other activities sometimes included or related to the design phase are data structure design, architectural design, interface design, and database design. The output of the design phase is typically a detailed design document that serves as a guide for the coders.

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48. If A, B and C are the angles of a triangle such that A: B: C=2: 3: 4,

If A, B and C are the angles of a triangle such that A: B: C=2: 3: 4, then what is the value of the following?
$$ \frac{\tan^2 B+1}{\tan^2 B-1} $$

4
2
1
0
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Let the angles of the triangle be A, B, and C. The ratio is given as A: B: C = 2: 3: 4.
The sum of angles in a triangle is 180°.
Let the common ratio factor be $x$. Then $A = 2x$, $B = 3x$, and $C = 4x$.
$2x + 3x + 4x = 180°$
$9x = 180°$
$x = \frac{180°}{9} = 20°$.

The angles are:
A = $2x = 2 \times 20° = 40°$
B = $3x = 3 \times 20° = 60°$
C = $4x = 4 \times 20° = 80°$

We need to find the value of the expression $\frac{\tan^2 B+1}{\tan^2 B-1}$.
Substitute $B = 60°$:
$\tan B = \tan 60° = \sqrt{3}$.
$\tan^2 B = (\sqrt{3})^2 = 3$.

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Now substitute this value into the expression:
$\frac{\tan^2 B+1}{\tan^2 B-1} = \frac{3+1}{3-1} = \frac{4}{2} = 2$.

The sum of angles in a triangle is 180°. Given the ratio of angles, the actual angle values can be determined. Evaluate trigonometric expressions by substituting the determined angle values and using standard trigonometric values for common angles like 60°.
The expression can also be simplified using trigonometric identities:
$\frac{\tan^2 B+1}{\tan^2 B-1} = \frac{\sec^2 B}{\frac{\sin^2 B}{\cos^2 B}-1} = \frac{\frac{1}{\cos^2 B}}{\frac{\sin^2 B – \cos^2 B}{\cos^2 B}} = \frac{1}{\sin^2 B – \cos^2 B}$.
Using the identity $\cos(2B) = \cos^2 B – \sin^2 B = -(\sin^2 B – \cos^2 B)$, the expression is $\frac{1}{-\cos(2B)}$.
For $B=60°$, $2B=120°$. $\cos(120°) = -\frac{1}{2}$.
The value is $\frac{1}{-(-\frac{1}{2})} = \frac{1}{\frac{1}{2}} = 2$.

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49. What is the angle in degree between the hour hand and the minute hand

What is the angle in degree between the hour hand and the minute hand of a clock when the time it shows is 5:20 PM?

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35°
40°
42°
45°
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At 5:20 PM, the time is 5 hours and 20 minutes.
First, calculate the angle of the hour hand from the 12 o’clock position.
The hour hand moves 360° in 12 hours, or 30° per hour (360°/12).
It also moves due to the minutes past the hour. In 60 minutes, the hour hand moves 30°. So, in 1 minute, it moves $30°/60 = 0.5°$.
At 5:20, the time is 5 hours and 20 minutes past 12. The total time in minutes past 12 is $(5 \times 60) + 20 = 300 + 20 = 320$ minutes.
Angle covered by hour hand = $320 \times 0.5° = 160°$.
Alternatively, angle = (5 hours $\times$ 30°/hour) + (20 minutes $\times$ 0.5°/minute) = 150° + 10° = 160°.

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Second, calculate the angle of the minute hand from the 12 o’clock position.
The minute hand moves 360° in 60 minutes, or 6° per minute (360°/60).
At 20 minutes past the hour, the minute hand is at the 20 minute mark.
Angle covered by minute hand = $20 \times 6° = 120°$.

The angle between the hour hand and the minute hand is the absolute difference between their positions.
Angle = $|160° – 120°| = 40°$.

The hour hand moves 0.5° per minute. The minute hand moves 6° per minute. The angle between the hands at H hours and M minutes past 12 is $|30H – 5.5M|$ degrees (where $5.5M = (6M – 0.5M)$, the difference in speeds). Using the position method: Hour hand angle = $30H + 0.5M$. Minute hand angle = $6M$. Angle = $|(30H + 0.5M) – 6M| = |30H – 5.5M|$. At 5:20, H=5, M=20. Angle = $|30 \times 5 – 5.5 \times 20| = |150 – 110| = 40°$.
Clock problems require understanding the relative speeds of the hour and minute hands. The 12-hour mark is usually taken as the reference point (0 degrees). Angles are measured clockwise from 12.

50. A wheel of circumference 2 m rolls on a circular path of radius 80 m.

A wheel of circumference 2 m rolls on a circular path of radius 80 m. What is the angle made by the wheel about the centre of the path, if it rotates 64 times on its own axis?

1.6 rad
1.4 rad
1.2 rad
0.8 rad
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The wheel has a circumference of 2 m. When the wheel rotates once on its own axis, the distance it covers rolling on a surface is equal to its circumference.
The wheel rotates 64 times on its own axis.
Total distance covered by the wheel rolling on the circular path = Number of rotations $\times$ Circumference of the wheel
Total distance = $64 \times 2$ m = 128 m.

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This distance is an arc length on the circular path. The formula relating arc length (s), radius (R), and the angle ($\theta$) subtended at the center (in radians) is $s = R \times \theta$.
Here, the arc length $s = 128$ m and the radius of the circular path $R = 80$ m.
So, $128 = 80 \times \theta$.
Solve for $\theta$:
$\theta = \frac{128}{80}$ radians.

Simplify the fraction:
$\theta = \frac{128 \div 16}{80 \div 16} = \frac{8}{5}$ radians.
$\frac{8}{5} = 1.6$ radians.

When a wheel rolls, the distance covered in one rotation is equal to its circumference. The arc length ($s$) of a sector in a circle is given by the formula $s = R\theta$, where $R$ is the radius and $\theta$ is the angle subtended at the center *in radians*.
The radius of the wheel itself ($\frac{1}{\pi}$ m) is not directly needed to solve this problem, as the distance covered is given by the circumference and the number of rotations. The problem asks for the angle subtended at the *centre of the path*, not the centre of the wheel.

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