Computer Science – Class 11 – Study material, Study notes of Computer science

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KENDRIYAVIDYALAYA SANGTHAN

REGIONALOFFICE,CHANDIGARH

(An Autonomous Body Under the Ministry of Education, Government of India)

COMPUTER SCIENCE

SESSION 2023- 24

CLASS-XI

ADVISORS

CO-ORDINATION TEAM

CONTENT TEAM

EXPERT CONTENT CREATER

ORGANISER

Mr. ASHOK KUMAR PGT (CS) KV KAPURTHALA

Mr. DEVENDER KUMAR PGT (CS) CHANDIGARH 3 BRD

Mr. ASHOK KUMAR BHUKAL PGT (CS) KV DAPPER

Mrs. Prreti Saxena,Deputy Commissioner,KVS RO CHANDIGARH

Sh. T Brahmanandam ,

Assistant Commissioner,

KVS RO CHANDIGARH

Sh Jugal Kishore ,

Assistant Commissioner,

KVS RO CHANDIGARH

Mr. SANJEET KUMAR SAGAR PRINCIPAL KV SECTOR 47 ,CHANDIGARH

Mr. SEEMA RATHOUR PGT CS KV SECTOR 47 ,CHANDIGARH

Mr. PARAMJEET SINGH ,PGTCS,KV NO. 5 BATHINDA CANTT

Ms. HARJEET KAUR , PGT CS, K V FEROZEPUR CANTT 2

Mr. HARTEJ SINGH, PGT CS, K V HUSSAINPUR NO 2

Mrs. AMARJEET KAUR , PGT CS , K V PATIYALA NO 3

Mr. D K JUNEJA , PGT CS GURDASPUR (TIBRI CANTT)

Mrs. MEENAKSHI SINGH PGT CS, PATHANKOT NO 3

Mr. CHANDRA PRAKASH MEENA PGT CS KV 4 BATHINDA CANTT

Computer Science Class - XI

Code No. 083

1. Learning Outcomes

Students should be able to:

a) develop basic computational thinking

b) explain and use data types

c) appreciate the notion of algorithms

d) develop a basic understanding of computer systems- architecture, operating

system, and cloud computing

e) explain cyber ethics, cyber safety, and cybercrime

f) understand the value of technology in societies along with consideration of gender

and disability issues.

2. Distribution of Marks

Unit No. Unit Name Marks Periods

Theory Practical

I Computer Systems and Organisation 10 10 10

II Computational Thinking and

Programming - 1

45 80 60

III Society, Law, and Ethics 15 20 —

Total 70 110 70

3. Unit wise Syllabus

Unit I: Computer Systems and Organisation

● Basic computer organisation: Introduction to Computer System, hardware, software, input

device, output device, CPU, memory (primary, cache and secondary), units of memory (

bit, byte, KB, MB, GB, TB, PB)

● Types of software: System software ( Operating systems, system utilities, device drivers),

programming tools and language translators ( assembler, compiler, and interpreter),

application software

● Operating System(OS): functions of the operating system, OS user interface

● Boolean logic: NOT, AND, OR, NAND, NOR, XOR, NOT, truth tables and De Morgan’s

laws, Logic circuits

● Number System: Binary, Octal, Decimal and Hexadecimal number system; conversion

between number systems

● Encoding Schemes: ASCII, ISCII, and Unicode (UTF8, UTF32)

Unit II: Computational Thinking and Programming - I

● Introduction to Problem-solving: Steps for Problem-solving (Analyzing the problem,

developing an algorithm, coding, testing, and debugging), representation of algorithms

using flowchart and pseudocode, decomposition

● Familiarization with the basics of Python programming: Introduction to Python, Features

of Python, executing a simple “hello world" program, execution modes: interactive mode

and script mode, Python character set, Python tokens( keyword, identifier, literal, operator,

punctuator), variables, concept of l-value and r-value, use of comments

● Knowledge of data types: Number(integer, floating point,complex), boolean,

sequence(string, list, tuple), None, Mapping(dictionary), mutable and immutable data

types.

● Operators: arithmetic operators, relational operators, logical operators, assignment

operators, augmented assignment operators, identity operators (is, is not), membership

operators (in not in)

● Expressions, statement, type conversion, and input/output: precedence of operators,

expression, evaluation of an expression, type-conversion (explicit and implicit conversion),

accepting data as input from the console and displaying output.

● Errors- syntax errors, logical errors, and run-time errors

● Flow of Control: introduction, use of indentation, sequential flow, conditional and iterative

flow

● Conditional statements: if, if-else, if-elif-else, flowcharts, simple programs: e.g.: absolute

value, sort 3 numbers and divisibility of a number.

● Iterative Statement: for loop, range(), while loop, flowcharts, break and continue

statements, nested loops, suggested programs: generating pattern, summation of series,

finding the factorial of a positive number, etc.

● Strings: introduction, string operations (concatenation, repetition, membership and slicing),

traversing a string using loops, built-in functions/methods–len(), capitalize(), title(), lower(),

upper(), count(), find(), index(), endswith(), startswith(), isalnum(), isalpha(), isdigit(),

islower(), isupper(), isspace(),lstrip(), rstrip(), strip(), replace(), join(), partition(), split()

● Lists: introduction, indexing, list operations (concatenation, repetition, membership and

slicing), traversing a list using loops, built-in functions/methods–len(), list(), append(),

extend(), insert(), count(), index(), remove(), pop(), reverse(), sort(), sorted(), min(), max(),

sum(); nested lists, suggested programs: finding the maximum, minimum, mean of numeric

values stored in a list; linear search on list of numbers and counting the frequency of

elements in a list.

● Tuples: introduction, indexing, tuple operations (concatenation, repetition, membership and

slicing); built-in functions/methods – len(), tuple(), count(), index(), sorted(), min(), max(),

sum(); tuple assignment, nested tuple; suggested programs: finding the minimum,

maximum, mean of values stored in a tuple; linear search on a tuple of numbers, counting

the frequency of elements in a tuple.

● Dictionary: introduction, accessing items in a dictionary using keys, mutability of a

dictionary (adding a new term, modifying an existing item), traversing a dictionary, built-in

● Input three numbers and display the largest / smallest number.

● Generate the following patterns using nested loops:

Pattern- 1 Pattern- 2 Pattern- 3

**

---

---

---

12345

1234

123

12

1

A AB

ABC

ABCD

ABCDE

● Write a program to input the value of x and n and print the sum of the following series:

⮚ 1 + 𝑥 + 𝑥

2

• 𝑥

3

• 𝑥

4

• ⋯ 𝑥

𝑛

⮚ 1 − 𝑥 + 𝑥

2

− 𝑥

3

• 𝑥

4

− ⋯ 𝑥

𝑛

⮚ 𝑥 +

𝑥

2

𝑥

3

𝑥

4

• ⋯

𝑥

𝑛

2 3 4 𝑛

⮚ 𝑥 +

𝑥

2

𝑥

3

𝑥

4

• ⋯

𝑥

𝑛

2! 3! 4! 𝑛!

● Determine whether a number is a perfect number, an Armstrong number or a palindrome.

● Input a number and check if the number is a prime or composite number.

● Display the terms of a Fibonacci series.

● Compute the greatest common divisor and least common multiple of two integers.

● Count and display the number of vowels, consonants, uppercase, lowercase characters instring.

● Input a string and determine whether it is a palindrome or not; convert the case of charactersin a

string.

● Find the largest/smallest number in a list/tuple

● Input a list of numbers and swap elements at the even location with the elements at the oddlocation.

● Input a list/tuple of elements, search for a given element in the list/tuple.

● Create a dictionary with the roll number, name and marks of n students in a class and displaythe

names of students who have marks above 75.

6. Suggested Reading Material

● NCERT Textbook for Computer Science (Class XI)

● Support Material on CBSE website

UNIT - 1

INTRODUCTION TO COMPUTER SYSTEM

A computer is an electronic device, under the control of instructions stored in its memory that can

accept data (input), process the data according to specified rules(Program) on processor & produces

information (output), and store the information for future use.

Data vs Information

Data are raw numbers or other findings which, by themselves, are of limited value.Information is data

that has been converted into a meaningfuland useful context.Computers are being used extensively

nowadays in

everyday life/every field

In the form of laptop, desktop, smartphone,gadgets etc.

Advantages of computer

• Speed
• Accuracy
• Huge storage
• Versatility
• Tirelessness

Disadvantages of computer

• Data security issue
• Computer crimes
• Health risk
• Bad impact on environment if not properly disposed off

Computer Components Any kind of computers consists of HARDWARE AND SOFTWARE.

Hardware: Computer hardware is the collection of physical elements/parts that constitutes a computer

system,such as the monitor, mouse, keyboard, computer data storage, hard drive disk (HDD), system

unit (graphic cards, sound cards, memory, motherboard and chips), etc. all of which are physical objects

& can be touched.

Software : Software is a generic term for organized collections of computer data and instructions,often

broken into two major categories: system software that provides the basic nontask- specific functions of

the computer, and application software which is used byusers to accomplish specific tasks.

Functional components of a computer

Central processing unit – Comprises three parts

key pressed by the user.

Mouse: A mouse is a small handheld input device which controls a cursor in a graphical user interface.

It can move and select text, files, folders etc. on our computer according to the user input.

Scanner: Scanner optically reads and document, file or image and then changes it into digital signal

and sends to the computer.

OMR: optical mark recognition/ reader, is used to read marks on a document and send them

tocomputer.

OCR: OCR stands for optical character Recognition, is an input device which reads printed text and

sends that to computer.

MICR: Magnetic Ink Character Reader is an input device which generally finds application is banks to

process cheques.

Microphone: it receives audio generated by some input source and sends it to a computer. Webcam: it

sends the captured images to a computer.

Graphics Tablets: This input device is used to draw using hand.

Trackballs: an upside down mouse ,encased within a socket. Is a cursor control device. Barcode

reader: It is used to read the barcode of various items and feed the same to computer. Gamepad: Also

known as joy pad is the input controller for video games.

Joystick: these input devices are used to control video games.

Output Devices

A device that can receive data from computer or another device and create output with that data is

called output device. Examples of various output devices are as :

Monitor: A monitor is an output device that is responsible for receiving data from a computer and

displaying that information as text or images for users to see.

Speakers: Receives sound signal from a computer and then plays that sound signal and thus we hear

songs or music or any other audio.

Projector: Gets data from a computer and displays or projects the same information onto a screen or a

wall. Projector cannot directly accept data from a user and send that data to another device.

TYPES OF SOFTWARE

Software is an organized instructions/code written by programmers using any of various special

computer languages for specific purpose.

Types of software:

(1) System software: controls the basic functions of a computer & hides complexity of computer

system from user and application software. E.g. Operating System, Compiler, Interpret etc.

(2) Application software: It handles specialized/ common tasks a user wants to perform, such as

banking, hotel management, any data processing, word processing etc.

(3) Utility software: Which helps to manage, maintain and control computer resources. E.g. are

antivirus software, backup software

1. System software

OPERATING SYSTEM

An Operating System (OS) is a system program that controls and manages the computer

resources(resource manager) so that application software can run on it.

Example: Microsoft Windows, Solaris, Linux, MAC OS,Ubuntu, Apple’s i-Phone OS etc.

HOW OPERATING SYSTEM WORKS

In any computer or mobile device, the operating system can be termed as the back bone when it comes

to software. This is because it has to be there before other programs can be run.It works as a

middleman (interface) between machine and user.

At the simplest level, an operating system does two things:

• It manages the hardware resources of the computer system. These resources include such

things as the processor, memory, disk space, etc.

• It provides a stable, consistent way for applications to deal with the hardware without having to

know all the details of the hardware.

FUNCTIONS OF OPERATING SYSTEM

• Processor management
• Memory management
• Device management
• Storage management
• Application interface
• User interface
• Process management
• Process a program in execution is known as process
• Handling of multiple processes at a time is known as process management.
• Process States

e.g. Payroll,HotelMgmt,HospitalMgmt,StockMgmt etc.

(3) Utility software/System Utilities

that assist OS in carrying out certain specialized tasks are called utility software.

Antivirus - An anti-virus scans the system for any virus and if detected, gets rid of it by deleting

or isolating it.

Compression tools - Compression tools are utilities that assist operating systems in shortening

files so that they take less space.

(3) Utility software/System Utilities

Disk Cleanup - Disk cleanup tools assist users in freeing up disk space.

Disk Defragmenter - Disk defragmenter is a disk management utility that increases file access

speeds by rearranging fragmented files on contiguous locations.

Backup - Backup utility enables backing up of files, folders, databases or complete disks.

File management tools - Utility software providing regular file management tasks like browse,

search, update, preview, etc. are called file management tools.

Restore – This utility restores the backup earlier taken.

Device driver or hardware driver is a group of files that enable one or more hardware devices

to communicate with the computer's operating system. Without drivers, the computer would not be

able to send and receive data correctly to hardware devices, such as a printer

MCQ

1. Smallest measurement unit of computer memory is?

(a) Megabyte

(b) Bit

(c) Byte

(d) Killo Byte

2. How many bytes are in 1 Kilobyte?

(a) 8 Bytes

(b) 128 Bytes

(c) 1024 Bytes

(d) 256 Bytes

3. Read Only Memory (ROM) is a memory.

(a) Non Volatile Memory

(b) Volatile Memory

(c) Both (a & b)

(d) None of these

4. Which of the following is designed to control the operations of a computer?

a) Application Software

b) System Software

c) Utility Software

d) User

5. The software designed to perform a specific task:

a) Synchronous Software

b) Package Software

c) Application Software

d) System Software

6. The software substituted for hardware and stored in ROM.

a) Synchronous Software

b) Package Software

c) Firmware

d) Middleware

7. Which of the following is not application software?

a) Windows 7

b) WordPad

c) Photoshop

d) MS-excel

Very Short Answer Questions

1. Namethesoftwarerequiredtomakeacomputerfunctional.Writedownitstwoprimaryservices

2. What is the need for secondary memory?

3. Draw the block diagram of a computer system. Briefly write about the functionality of each

component.

Short Answer Questions

1. State the basic units of Computer along with its sub units and their functions.

2. Differentiate between RAM and ROM.

3. What is the role of CPU in Computer System?

Long Answer Questions

1. Name any four secondary storage media.

2. Define software. Explain with examples- System Software, Utility Software and

Application Software.

3. Write short notes on Assembler, Compiler and Interpreter.

For any two finite sets A and B

(i) (A+B)’=A’.B’

(ii) (A. B)’=A’+B’

Truth table

A truth table is a mathematical table used in logic. e.g.

Logic Gates

Logic gate is an idealized or physical device implementing a Boolean function. These are used to

construct logic circuit.

Universal gates are the logic gates which are capable of implementing any Boolean function without

requiring any other type of gate.

Types of Universal Gates-

In digital electronics, there are only two universal gates which are-

1. NAND Gate
2. NOR Gate

Number System & Encoding Schemes

In general term computer represent information in different types of data forms i.e. number , character

,picture ,audio , video etc.

Computers are made of a series of switches/ gates. Each switch has two states: ON(1) or OFF(0).That's

why computer works on the basis of binary number system(0/1).But for different purpose different

number systems are used in computer world to represent information. E.g. Octal, Decimal, Hexadecimal.

CONVERSIONS

DECIMAL TO OTHER

1. DECIMAL TO BINARY

Decimal Number System to Other Base

To convert Number system from Decimal Number System to Any Other Base is quite easy;you

have to follow just two steps:

A) Divide the Number(Decimal Number)by the base of target base system(in which you want to

convert the number:Binary (2),octal (8)and Hexadecimal(16)).

B) Write the remainder from step1 as a Least Signification Bit(LSB)to Step last as a Most

significant Bit(MSB).

2. DECIMAL TO OCTAL

Decimal to Octal Conversion Result

Decimal Number is: (12345) 10

Octal Number is

3. DECIMAL TO HEXADECIMAL

Decimal to Hexadecimal

Conversion

Result

Example

Decimal Number is: (12345) 10

Hexadecimal Number

is (3039) 16

Example

Decimal Number is: (725) 10

Hexadecimal Number is

(2D5)

Convert

To its equivalent...A,B,C,D,E,F

BINARY TO OTHER

A) Multiply thedigit with 2(with place value exponent).Eventually add all the multiplication

becomes the Decimal number.

1. BINARY TODECIMAL

2. BINARY TO OCTAL

An easy way to convert from binary to octal is to group binary digits into sets of three, starting with

the least significant (rightmost)digits.

Binary:

011 100 101 Pad the most significant digits with zeros

if necessary to complete a group of three.

Then,lookup each group in a table:

Binary: 000 001 010 011 100 101 110 111

Octal: 0 1 2 3 4 5 6 7

Binary= 011 100 101

Octal = 3 4 5 = 345oct