Class 9 Computer Chapter 2 Notes

Important MCQs and Short Questions of Class 9 Computer Chapter 2 Notes in 9th Class Computer Science Urdu Medium written by Sir Saud Khan. These computerized notes are very helpful in the preparation of Class 9 Computer Binary System for students of Class 9 Computer Chapter 2 Notes these are according to the paper patterns of all Punjab boards.

• Here are the detailed 9th class computer chapter 2 notes to help you prepare for your exams.
• Binary System Multiple Choice Questions ( MCQs ) with correct Answers and short questions
• Introduction to Number Systems: A number system is the system for representation of numeric data. We all are familiar with decimal number system where each number consists of digits from 0 to 9. In a computer system, other number systems are also used. We discuss few number systems in the following sections.
• Decimal: The number system we use in our daily life is the decimal number system. The decimal number system has base 10 as it uses ten digits [0-9]. Each position represents a specific power of base 10.
• Examples: 892 = 8 x 10^2 + 9  x 10^1 + 2 × 10^0
• 1247 = 1 x 10^3 + 2 x 10^2 + 4×10^1 + 7 × 10^0
• 53 = 5 x 10^1 + 3 × 10^0
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• Binary: Binary number system has base 2 as all the numbers in this system consist of only two digits i.e. 0 and 1. Digital computers use this system to store data. Your name is in the form of alphabets, but for a computer each alphabet has some binary value.
• Example: The binary value of the letter 'A' is 01000001 and its decimal value is 65.
• Hexadecimal: Hexadecimal system has total 16 numbers, i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, where A = 10 , B = 11 , C = 12 , D = 13 , E = 14 and F = 15
• Number System Conversion: We can convert a number from one number system to another and vice versa. In the following, we discuss conversions among different number systems.
• Decimal to Binary and Binary to Decimal: Decimal to Binary: To convert a decimal number to binary, we divide the number by 2 and take quotient and remainder. We continue dividing the quotient by 2 until we get quotient 0. We write out all the remainders in reverse order to obtain the value in binary.
• Our comprehensive class 9 computer chapter 2 notes pdf lecture in urdu will ensure you're fully prepared for your exams.
• Example: The method to solve this problem. Remainders are taken from bottom to top to present the binary number. So, 156 10 = 1010011100 2.
• Volatile Memory (Primary Storage): A device which holds data as long as it has power supply connected to it, is called Volatile Memory. Its best example is Random Access Memory (RAM), which holds memory only as long as it is connected to power source. As soon as the power supply is disconnected, all the data in RAM is cleared.
• Non-Volatile Memory (Secondary Storage): A device which can hold data even if it is not connected to any power source, is called Non Volatile Memory. The typical examples for Non Volatile Memory are hard drives, flash drives and memory cards installed in cell phones. Even if you turn off your PC, the data in your hard drive or flash drive stays intact.
• Data Representation in Computer Memory: Digital computers store data in binary form. It means that whether it is a text, picture, movie or some application, it is stored in computer's memory in the form of Os and 1s. All the characters on your keyboard has an associated code in binary. This code is called ASCII code of the character. ASCII stands for American Standard Code for Information Interchange. It is a de-facto standard for representation of data inside computer's memory. Table presents the ASCII table which shows the code against each character on your keyboard.