Vanavani Mat. Hr. Sec. School Subject : Computer Science Std: XI Quarterly Exam Key Part I (15 X 1 = 15) 1. d 2. A 3. C 4. D 5. D 6. c 7. B 8. A 9. D 10. B 11. d 12. C 13. D 14. A 15. A Part B -Any Six Q. No. 18 Compulsory(6 X 2 = 12) 16. A computer can be defined as an automatic electronic machine for performing calculations or controlling operations that are expressible in numerical or logical terms. The computer is also capable of storing information, which can be used later. It can process millions of instructions in a few seconds and at the same time with high accuracy. 17. The hardware devices attached to the computer are called peripheral equipment. Peripheral equipment includes all input, output and secondary storage devices. 18. (i) 11010 Convert to decimal then decimal to Hexa-decimal 1A (ii) 111101000010 Convert to decimal then decimal to Hexa-decimal F42 19. The arithmetic and logic unit (ALU) is the part of CPU where actual computations take place. The ALU is the computer s calculator. It executes arithmetic and logical operations. The arithmetic operations include addition, subtraction, multiplication and division. The logical operation compares numbers, letters and special characters. The ALU also performs logic functions such as AND, OR and NOT. 20. Operations on memories are called reads and writes, defined from the perspective of a processor or other device that uses a memory: a write instruction transfers information from other device to memory and a read instruction transfers information from the memory to other devices. 21. If the logic circuit outputs are based on the inputs presented at that time, then they are called combinational circuit. The half adder and full adder circuits are the examples for the combinational circuits. 22. The Operating System comes under the System Software category. Operating System is the intermediary or an interface between the user and computer hardware. Operating System is one program running at all times on the computer. 23. (i) TCP stands for transmission control protocol. TCP breaks up the data to be sent into little packets. It guarantees that any data sent to the destination computer reaches intact. It makes the process appear as if one computer is directly connected to the other.
(ii) IP stands for Internet Protocol. IP is a set of conventions used to pass packets from one host to another. It is responsible for routing the packets to a desired destination IP address. 24. Files are broadly classified into two categories: Application Files: Application files (also called Program files) are files which can do something. Document Files: Document files are files that are created by the user using an application. Part C Any Six Q. No. 30 Compulsory(6 X 3 = 18) 25. Data is defined as an un-processed collection of raw facts in a manner suitable for communication, interpretation or processing. Stored facts Inactive Technology based Gathered from various sources. information is a collection of facts from which conclusions may be drawn which is used to reveal the underlying meaning. Processed facts Active Business based Transformed from data. 26. word processing software lets you create, edit, format, store and print text and graphics. Some of the commonly used word processors are Microsoft Word, WordStar, WordPerfect. 27. 11011001 + 1011101 11011001 1011101 100110110 28. Output is anything that comes out of a computer. An output device is capable of presenting information from a computer. The monitors and printers are commonly used output devices. 29. The major functional units of the computer system remain the same : input, processing, storage and output. Input Unit - Output Unit - Central Processing Unit - Memory Unit
30. C = A AND B, C = A. B 31. there are two types of the Operating Systems. They are Single user Operating System : At a time, only one user can operate the system. MS DOS Multi-user Operating System : More than one user can operate the same system simultaneously. Unix 32. The following are the general types of networks Local Area Network (LAN) Metropolitan Area Network (MAN) Wide Area Network (WAN) 33. Part D- Either Or ( 5 X 5 = 25) 34.a. Software can be classified into two categories: System Software and Application Software. System software consists of general programs written for a computer. These programs provide the environment to run the application programs. System software comprises programs, which interact with the hardware at a very basic level. System software serves as the interface between hardware and the user. The operating system, compilers and utility programs are examples of system software. An operating system is an integrated set of specialized programs that is used to manage the overall operations of a computer. It acts like an interface between the user, computer hardware and software. Unix, Windows The compiler software translates the source program (user written program) into an object program (binary form). C, C++
The utility programs support the computer for specific tasks like file copying, sorting, linking a object program, etc. An Application Software consists of programs designed to solve a user problem. It is used to accomplish specific tasks rather than just managing a computer system. The commonly used Application Software packages are word processor, spread sheet, database management system. This software lets you create, edit, format, store and print text and graphics. Some of the commonly used word processors are Microsoft Word, WordStar, WordPerfect. Spreadsheet software packages allow the user to manipulate numbers. Microsoft Excel, Lotus 1-2-3. A database management system is a collection of programs that enable to store, modify and extract information from a database. Microsoft Access, Oracle. 34. b. A B C A+B+C 0 0 0 0 0 0 1 1 0 1 0 1 0 1 1 1 1 0 0 1 1 0 1 1 1 1 0 1 1 1 1 1 35.a. RAM, ROM, PROM, EPROM, EEPROM each 3 points 35.b. C = A B + A B, C = A + B 36.a. Process management undertakes the allocation of processors to one program. The Operating System controls the jobs submitted to the system (CPU). Several algorithms are used to allocate the job to the processor. Algorithm is a step-by-step method to solve a given problem. 1.FIFO. 2.SJF 3.Round Robin. 4.Based on Priority. Explanation with eg The allocation of processors by process management is also known as the CPU Scheduling.
36.b. The different roles taken by OS are 1 User Interface 2 Memory management 3 Process management 4 File management 5 Networking Capabilities management 6 Security Management 7 Fault tolerance 8 Application Base 9 Distributed Operating System.( brief out each) 37.a The network topology is the structure or layout of the communication channels that connects the various computers on the network. Each computer in the network is called a node. The factors that determine the topology are the type of nodes, the expected performance, type of wiring used and the cost. Network can be laid out in different ways. The five common topologies are star, ring, bus, hybrid and FDDI. ( explanation for each ) 37. b. World Wide Web Web is a multimedia portion of the Internet. It consists of an interconnection system of sites or servers all over the world that can store information in the multimedia form. The Multimedia sites include text, animated graph, voice and images. E-mail - The World Wide Web is getting a lot of attention due to its main attraction of Electronic mail. Electronic mail is usually used to exchange messages and data files. Usenet News Groups: Electronic discussion groups. User network abbreviated as usenet is essentially a giant disbursed bulletin board. Electronic discussion groups that focus on specific topic forms, computer forums. Mailing list: Email based discussion groups combining E-mail, news groups and mailing lists send messages on a particular subject. Automatically messages reach the mailbox of that group. FTP: File Transfer Protocol, abbreviated as FTP is used for the net user for transferring files around the world. The transfer includes software, games, photos, maps, music and such other relevant materials. Telnet: Telnet is a protocol that allows the user to connect to a remote computer. This feature is used to communicate a microcomputer with mainframe. Popular uses of the web are Research, Chatting, Free-wares, Education online, Online services, Job searches 38.a. The Control Panel allows you to install and manage the different hardware components attached to your computer. It is used to modify the system and hardware
settings of your computer. To open the Control Panel window click on the Start button, and then Control Panel. brief description of each 38.b. Paint is an application that lets you draw and colour pictures. To start Paint, click on Start-> All Programs ->Accessories ->Paint