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Question a
a) What does ASCII stand for?
Answer a
ASCII stands for American Standard Code for Information Interchange.
It is a character encoding standard used to represent letters, numbers, symbols, and control characters inside a computer. In this chapter, ASCII is included under the topic of internal storage encoding of characters.
Thus, ASCII helps the computer store and process text in a standard coded form.
Question b
b) What does the base of a Number system mean?
Answer b
The base of a number system, also called its radix, means the total number of digits or symbols used in that number system. It tells us how many different symbols are available for writing numbers in that system.
For example:
•
Decimal system has base 10, so it uses the digits 0 to 9
•
Binary system has base 2, so it uses 0 and 1
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Octal system has base 8, so it uses digits 0 to 7
•
Hexadecimal system has base 16, so it uses 0 to 9 and A to F
Thus, the base shows the counting limit of a number system before the next place value is used.
Question c
c) What is the base of Decimal, Binary, Octal and Hexadecimal number systems?
Answer c
The base of these number systems is as follows:
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Decimal number system – Base 10
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Binary number system – Base 2
•
Octal number system – Base 8
•
Hexadecimal number system – Base 16
The base of a number system tells the total number of digits or symbols used in that system. Therefore, the decimal system uses 10 digits, the binary system uses 2 digits, the octal system uses 8 digits, and the hexadecimal system uses 16 symbols.
Question d
d) How many digits are there in a Binary number system?
Answer d
The Binary number system has 2 digits, namely 0 and 1.
It is a number system with base 2, so only these two digits are used to represent all values. In a digital computer, binary digits are used because they can be easily shown by the presence (1) or absence (0) of current or voltage.
Thus, the binary number system contains only two digits: 0 and 1.
Question e
e) Which digits are used in Hexadecimal number system?
Answer e
The Hexadecimal number system uses the digits 0 to 9 and the letters A, B, C, D, E, and F.
So, the symbols used are:
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9
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A, B, C, D, E, F
In this number system, the letters represent values greater than 9:
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A = 10
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B = 11
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C = 12
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D = 13
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E = 14
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F = 15
Thus, the hexadecimal number system uses a total of 16 symbols.
Question f
f) What is Unicode? How is it useful?
Answer f
Unicode is a universal character coding standard adopted by modern platforms. It is promoted by the Unicode Consortium. In Unicode, every character is given a unique number, regardless of the platform, program, or language.
Unicode is useful because it supports the worldwide interchange, processing, and display of written text in many different languages. This means the same text can be stored, shared, and displayed correctly across different computer systems and software.
Thus, Unicode makes it possible to handle characters of diverse languages in a standard and reliable way.
Question g
g) Distinguish between ASCII and ISCII.
Answer g
Basis
ASCII
ISCII
Full form
ASCII stands for American Standard Code for Information Interchange.
ISCII stands for Indian Standard Code for Information Interchange.
Purpose
It is used as a standard code for representing characters in computers.
It was developed to facilitate the use of Indian languages on computers.
Number of bits
ASCII-7 can represent 128 characters, and ASCII-8 can represent 256 characters.
ISCII is an 8-bit code, and each character in ISCII needs 8 bits.
Language support
It is mainly used for standard English characters and symbols.
It allows English and Indian script alphabets to be used simultaneously.
Standardization
ASCII is a standard character code used widely in computers.
ISCII was adopted in 1991 by the Bureau of Indian Standards.
Thus, ASCII is a general character coding standard mainly for English characters, whereas ISCII is an 8-bit coding standard specially designed to support Indian languages along with English.
Question h
h) Do as directed :
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Convert the Decimal number 781 to its Binary equivalent.
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Convert Binary number 101101.001 to its decimal equivalent
•
Convert Octal number 321.7 into its Binary equivalent
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Convert the Hexadecimal number 3BC into its Binary equivalent
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Convert the Binary number 10011010.010101 to its Hexadecimal equivalent
•
Convert the Decimal number 345 into Octal number.
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Convert the Decimal number 736 into Hexadecimal number.
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Convert the Octal number 246.45 into Hexadecimal number.
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Convert the Hexadecimal number ABF.C into Octal number.
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Convert the Octal number 576 to Decimal.
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Convert the Hexadecimal number A5C1 to Decimal.
Answer h
The required conversions are given below.
1) Convert the Decimal number 781 to its Binary equivalent.
By repeated division by 2 and writing the remainders in reverse order, the binary equivalent is:
(781)10 = (1100001101)22) Convert Binary number 101101.001 to its decimal equivalent.
For the integer part:
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(101101)2 = 32 + 8 + 4 + 1 = 45For the fractional part:
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(.001)2 = 1/8 = 0.125Therefore,
(101101.001)2 = (45.125)103) Convert Octal number 321.7 into its Binary equivalent.
Each octal digit is replaced by its 3-bit binary form:
•
3 -> 011•
2 -> 010•
1 -> 001•
.7 -> .111So,
(321.7)8 = (11010001.111)24) Convert the Hexadecimal number 3BC into its Binary equivalent.
Each hexadecimal digit is replaced by its 4-bit binary form:
•
3 -> 0011•
B -> 1011•
C -> 1100Therefore,
(3BC)16 = (001110111100)2(Leading zeros may also be omitted:
11101111002)5) Convert the Binary number 10011010.010101 to its Hexadecimal equivalent.
Group the binary digits in sets of 4 from the decimal point:
•
Integer part:
1001 1010 -> 9 A•
Fractional part:
0101 0100 -> 5 4So,
(10011010.010101)2 = (9A.54)166) Convert the Decimal number 345 into Octal number.
By repeated division by 8 and writing the remainders in reverse order:
(345)10 = (531)87) Convert the Decimal number 736 into Hexadecimal number.
By repeated division by 16:
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736 / 16 = 46 remainder 0•
46 / 16 = 2 remainder 14 (E)•
2 / 16 = 0 remainder 2Therefore,
(736)10 = (2E0)168) Convert the Octal number 246.45 into Hexadecimal number.
First convert octal to binary:
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2 -> 010•
4 -> 100•
6 -> 110•
.4 -> .100•
5 -> 101So binary form is:
010100110.1001012 = 10100110.1001012Now group into 4 bits for hexadecimal:
•
Integer part:
1010 0110 -> A 6•
Fractional part:
1001 0100 -> 9 4Hence,
(246.45)8 = (A6.94)169) Convert the Hexadecimal number ABF.C into Octal number.
First convert hexadecimal to binary:
•
A -> 1010•
B -> 1011•
F -> 1111•
.C -> .1100So binary form is:
101010111111.11002Now group into 3 bits for octal:
•
Integer part:
101 010 111 111 -> 5 2 7 7•
Fractional part:
110 000 -> 6 0So,
(ABF.C)16 = (5277.6)810) Convert the Octal number 576 to Decimal.
Expand according to powers of 8:
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5 x 82 = 5 x 64 = 320•
7 x 81 = 7 x 8 = 56•
6 x 80 = 6 x 1 = 6Total:
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320 + 56 + 6 = 382Therefore,
(576)8 = (382)1011) Convert the Hexadecimal number A5C1 to Decimal.
Expand according to powers of 16:
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A = 10•
10 x 163 = 10 x 4096 = 40960•
5 x 162 = 5 x 256 = 1280•
C = 12; 12 x 161 = 192•
1 x 160 = 1Total:
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40960 + 1280 + 192 + 1 = 42433Therefore,
(A5C1)16 = (42433)10