UPSC CISF-AC-EXE

What is used for deciding priority to allocate CPU time to a process?

[amp_mcq option1=”Linker” option2=”Scheduler” option3=”Loader” option4=”Debugger” correct=”option2″]

The correct option is B.

In an operating system, the Scheduler (specifically, the CPU scheduler) is responsible for deciding which process among the ready processes should be allocated the CPU. Scheduling algorithms often use priority as a key factor in making this decision, giving higher priority processes preferential access to the CPU. Linkers, loaders, and debuggers are software tools involved in the development and execution lifecycle but are not primarily responsible for runtime CPU allocation priority.

The CPU scheduler implements various scheduling algorithms like First-Come, First-Served (FCFS), Shortest Job Next (SJN), Priority Scheduling, Round Robin, etc. Priority scheduling uses a priority value associated with each process to select the next process to run.

In MS-Excel 2007, STDEV[numberl, number 2, …] is a statistical function that

[amp_mcq option1=”estimates standard deviation based on a sample by ignoring logical values and text in the sample” option2=”estimates standard deviation based on a sample by including logical values and text in the sample” option3=”calculates standard deviation based on the entire population by ignoring logical values and text” option4=”calculates standard deviation based on the entire population by including logical values and text” correct=”option1″]

The correct option is A.

In MS-Excel 2007 (and later versions with STDEV.S), the STDEV function (or STDEV.S) calculates the standard deviation based on a *sample*. It measures the dispersion or spread of data points around the mean. Importantly, the standard STDEV function in Excel ignores logical values (TRUE/FALSE) and text within the range of numbers provided as arguments when calculating the standard deviation.

Excel has other standard deviation functions: STDEVP (STDEV.P) for calculating the standard deviation of an *entire population*, which also ignores text and logical values; STDEVA for sample standard deviation that *includes* text (counted as 0) and logical values; and STDEVPA for population standard deviation that *includes* text and logical values. The question specifically asks about `STDEV`.

In MS-Excel 2007, NPV(rate, value1, [value 2], …) is a financial function that returns

[amp_mcq option1=”the net present value of an investment based on discount rate and series of future payments and income” option2=”the number of periods for an investment based on periodic, constant payments and constant interest rate” option3=”the future value of an investment based on periodic, constant payments and constant interest rate” option4=”the future value of an initial principal after applying a series of compound interest rates” correct=”option1″]

The correct option is A.

In MS-Excel, the NPV (Net Present Value) function calculates the present value of a series of cash flows based on a specified discount rate. It is used to evaluate the profitability of an investment or project by bringing all future cash flows (both positive and negative) back to their present-day value. Option A accurately describes this function: “the net present value of an investment based on discount rate and series of future payments and income”.

The NPV function assumes that cash flows occur at the end of each period. If cash flows occur at the beginning of the period, the NPV calculation needs adjustment, often by using the XNPV function for uneven dates or a combination of NPV and the initial investment outside the function.

Which one of the following communication media uses light pulses for carrying information?

[amp_mcq option1=”Coaxial cable” option2=”Optic fibre” option3=”Microwave” option4=”Satellite” correct=”option2″]

The correct option is B.

Communication media carry information in various forms. Coaxial cables use electrical signals transmitted through copper wires. Microwave and satellite communication use electromagnetic waves (radio waves) transmitted through the air or space. Optic fibre cables, however, use light pulses transmitted through thin strands of glass or plastic. This method allows for very high bandwidth and long-distance transmission with minimal signal loss.

Optical fibre communication has revolutionized telecommunications and data networking due to its speed, capacity, and immunity to electromagnetic interference compared to traditional copper-based media.

In the context of computer graphics, which one of the following is not a raster image format?

[amp_mcq option1=”JPEG” option2=”TIFF” option3=”SVG” option4=”GIF” correct=”option3″]

The correct option is C.

Raster image formats represent images as a grid of pixels (Picture Elements), where each pixel has a color value. Examples include JPEG, TIFF, GIF, PNG, and BMP. Vector image formats, however, represent images using mathematical equations to define lines, curves, and shapes. They are resolution-independent and can be scaled without loss of quality. SVG (Scalable Vector Graphics) is a prominent example of a vector image format.

Raster images are suitable for photographs and complex images with gradients and subtle color variations but can become pixelated when scaled up significantly. Vector images are ideal for logos, illustrations, and graphics that require scalability, such as for printing at different sizes.

In the context of computer networks, which one of the following is not an application layer protocol?

[amp_mcq option1=”SMTP” option2=”FTP” option3=”HTTP” option4=”TCP” correct=”option4″]

The correct option is D.

In the context of computer networks using the TCP/IP model, the Application Layer is the highest layer, which interacts directly with software applications. Protocols at this layer provide specific services to applications. SMTP (Simple Mail Transfer Protocol), FTP (File Transfer Protocol), and HTTP (Hypertext Transfer Protocol) are all well-known application layer protocols used for email, file transfer, and web browsing, respectively. TCP (Transmission Control Protocol), on the other hand, is a Transport Layer protocol. It provides reliable, connection-oriented data transmission services to the application layer, ensuring data integrity and flow control.

The TCP/IP model consists of four layers: Network Interface Layer, Internet Layer, Transport Layer, and Application Layer. The Transport Layer is responsible for end-to-end data transfer between processes. Other common Transport Layer protocols include UDP (User Datagram Protocol).