Chapter 2 Number System Class 11 Computer Science NCERT Solution

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Encoding Scheme & Number System Class 11 Computer Science NCERT Solution


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.

Q2. Give full form of ASCII and ISCII.

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

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

Q5. Express the following octal numbers into their equivalent decimal numbers.

(i) 145

(ii) 6760

(iii) 455

(iv) 10.75

Q6. Express the following decimal numbers into hexadecimal numbers.

(i) 548

(ii) 4052

(iii) 58

(iv) 100.25

Q7. Express the following hexadecimal numbers into equivalent decimal numbers.

(i) 4A2

(ii) 9E1A

(iii) 6BD

(iv) 6C.34

Q8. Convert the following binary numbers into octal and hexadecimal numbers.

(i) 1110001000

(ii) 110110101

(iii) 1010100

(iv) 1010.1001

Q9. Write binary equivalent of the following octal numbers.

(i) 2306

(ii) 5610

(iii) 742

(iv) 65.203

Q10. Write binary representation of the following hexadecimal numbers.

(i) 4026

(ii) BCA1

(iii) 98E

(iv) 132.45

Q11. How does computer understand the following text?
(hint: 7 bit ASCII code).

(i) HOTS

(ii) Main

(iii) CaSe

Q12. The hexadecimal number system uses 16 literals(0–9, A–F). 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.

Q14. Write the equivalent hexadecimal and binary values for each character of the phrase given below.
‘‘ हम सब एक”

Q15. What is the advantage of preparing a digital content in Indian language using UNICODE font?

Q17. Encode the word ‘COMPUTER’ using ASCII and convert the encode value into binary values.

Number System Class 11 Computer Science

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