Encoding Scheme & Number System Class 11 Computer Science NCERT Solution
SUMMARY
Encoding scheme maps text into the codes that facilitate communication among computers.
Textual data is encoded using ASCII, ISCII or Unicode.
Unicode scheme is a character encoding standard which can encode all the characters of almost all
languages of the world.
Computer being a digital system understands only binary numbers which are 0 and 1.
Encoded text is converted to binary form for processing by the computer.
Octal and hexadecimal number systems are used to simplify the binary coded representation as they
allow grouping of 3 or 4 bits of binary numbers each, respectively. Q1. Write base values of binary, octal and hexadecimal number system.
Base value of Octal – 8 Base value of Hexadecimal – 16
Q2. Give full form of ASCII and ISCII.
ASCII : American Standard Code for Information Interchange ISCII : Indian Script Code for Information Interchange
Q3. Try the following conversions. (Number after bracket is showing the base)
(i) (514)8 = (?)10
(ii) (220)8 = (?)2
(iii) (76F)16 = (?)10
(iv) (4D9)16 = (?)10
(v) (11001010)2 = (?)10
(vi) (1010111)2 = (?)10
ii) (220)8 = (10010000)2 iii) (76F)16 = (1903)10 iv) (4D9)16 = (1241)10 v) (11001010)2 = (202)10 vi) (1010111)2 = (87)10
Q4. Do the following conversions from decimal number to other number systems.
(i) (54)10 = (?)2
(ii) (120)10 = (?)2
(iii) (76)10 = (?)8
(iv) (889)10 = (?)8
(v) (789)10 = (?)16
(vi) (108)10 = (?)16
(ii) (120)10 = (1111000)2 (iii) (76)10 = (114)8 (iv) (889)10 = (1571)8 (v) (789)10 = (315)16 (vi) (108)10 = (6C)16
Q5. Express the following octal numbers into their equivalent decimal numbers.
(i) 145
(ii) 6760
(iii) 455
(iv) 10.75
(ii) (6760)8 = (3568)10 (iii) (455)8 = (301)10 (iv) (10.75)8 = (8.953125)10
Q6. Express the following decimal numbers into hexadecimal numbers.
(i) 548
(ii) 4052
(iii) 58
(iv) 100.25
(ii) (4052)10 = (FD4)16 (iii) (58)10 = (3A)16 (iv) (100.25)10 = (64.4)16
Q7. Express the following hexadecimal numbers into equivalent decimal numbers.
(i) 4A2
(ii) 9E1A
(iii) 6BD
(iv) 6C.34
(ii) (9E1A)16 = (40474)10 (iii) (6BD)16 = (1725)10 (iv) (6C.34)16 = (108.203125)10
Q8. Convert the following binary numbers into octal and hexadecimal numbers.
(i) 1110001000
(ii) 110110101
(iii) 1010100
(iv) 1010.1001
(ii) (110110101)2 = (665)8 = (1B5)16 (iii) (1010100)2 = (124)8 = (54)16 (iv) (1010.1001)2 = (12.44)8 = (A.9)16
Q9. Write binary equivalent of the following octal numbers.
(i) 2306
(ii) 5610
(iii) 742
(iv) 65.203
(ii) (5610)8 = (101110001000)2 (iii) (742)8 = (111100010)2 (iv) (65.203)8 = (110101.010000011)2
Q10. Write binary representation of the following hexadecimal numbers.
(i) 4026
(ii) BCA1
(iii) 98E
(iv) 132.45
(ii) (BCA1)16 = (1011110010100001)2 (iii) (98E)16 = (100110001110)2 (iv) (132.45)16 = (100110010.010001012)
Q11. How does computer understand the following text?
(hint: 7 bit ASCII code).
(i) HOTS
ASCII value of H is 72 and its equivalent 7-bit binary code = 1001000 ASCII value of O is 79 and its equivalent 7-bit binary code = 1001111 ASCII value of T is 84 and its equivalent 7-bit binary code = 1010100 ASCII value of S is 83 and its equivalent 7-bit binary code = 1010011 Binary equivalent of complete word “HOTS” is given below : HOTS = 1001000100111110101001010011 H O T S ASCII Code 72 79 84 83 Binary Code 1001000 1001111 1010100 1010011
(ii) Main
ASCII value of ‘M’ is 77 and its equivalent 7-bit binary code = 1001101 ASCII value of ‘a’ is 97 and its equivalent 7-bit binary code = 1100001 ASCII value of ‘i’ is 105 and its equivalent 7-bit binary code = 1101001 ASCII value of ‘n’ is 110 and its equivalent 7-bit binary code = 1101110 Binary equivalent of complete word “Main” is given below : Main = 1001101110000111010011101110 M a i n ASCII Code 77 97 105 110 Binary Code 1001101 1100001 1101001 1101110
(iii) CaSe
ASCII value of ‘C’ is 67 and its equivalent 7-bit binary code = 1000011 ASCII value of ‘a’ is 97 and its equivalent 7-bit binary code = 1100001 ASCII value of ‘S’ is 83 and its equivalent 7-bit binary code = 1010011 ASCII value of ‘e’ is 101 and its equivalent 7-bit binary code = 1101110 Binary equivalent of complete word “CaSe” is given below : CaSe = 1000011110000110100111100101C a S e ASCII Code 67 97 83 101 Binary Code 1000011 1100001 1010011 1100101
Q12. The hexadecimal number system uses 16 literals(0โ9, AโF). Write down its base value.
Q13. Let X be a number system having B symbols only. Write down the base value of this number system.
As we know the number of symbols is equal to base number like in binary there are two symbols so base value is two similarly in Octal, Decimal and Hexadecimal
Q14. Write the equivalent hexadecimal and binary values for each character of the phrase given below.
โโ เคนเคฎ เคธเคฌ เคเคโ
Symbol Hexadecimal Binary เคน 0939 100100111001 เคฎ 092E 100100101110 เคธ 0938 100100111000 เคฌ 092C 100100101100 เค 090F 100100001111 เค 0915 100100010101
Q15. What is the advantage of preparing a digital content in Indian language using UNICODE font?
Q17. Encode the word โCOMPUTERโ using ASCII and convert the encode value into binary values.
Binary code of ‘COMPUTER’ is : 10000111001111100110110100001010101101010010001011010010 Symbol ASCII Binary Code C 67 1000011 O 79 1001111 M 77 1001101 P 80 1010000 U 85 1010101 T 84 1010100 E 69 1000101 R 82 1010010
Number System Class 11 Computer Science
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