Page 69 - Computer Science Class 11 With Functions
P. 69
Case Based Questions
1. Nirankar has just learnt about the hexadecimal number system. With his previous knowledge of the decimal number
system, he knows how to compute the value using the place value and face value of symbols given in the number. He has
computed the decimal value of the hexadecimal number system, (D20.B1) as given below:
16
(D20.B1) 16
1
2
0
-1
= D × 16 + 2 × 16 + 0 × 16 + B × 16 + 1 × 16 -2
= 13 × 1 + 2 × 16 + 0 × 256 + 11 × 0.0625 + 1 × 0.0039
= 13 + 32 + 0 + 0.6875 + 0.0039
= (45.6914) 2
Is the computation correct? If not, give the correct computation.
2. Sheikh just came to know that hexadecimal numbers are used to represent colors in digital form. He knows that red, green,
and blue are the three primary colors, referred to as RGB. He has formed a table that gives the name of the color along with
its decimal value and hexadecimal value. Help him complete the table.
Name of Colour Decimal Value Hexadecimal Value
Yellow (FF, FF, 00)
(256, 0, 0)
Blue (0, 0, 255)
Black
Green (00, FF, 00)
3. Saptarishi is learning about ASCII, which is a 7-bit encoding scheme to codify 128 different characters. He now wants to
encode the following words using ASCII and thereafter write their binary equivalent. Help him complete the task. You may
refer to ASCII table given in the chapter.
Word ASCII Code Binary equivalent
BOT 66 79 84
KEY 75 68 89
NUMber 1001110 1010101 1001101 1100010
1100101 1110010
Yes-NO
Multiple Choice Questions
1. (a) 2. (d) 3. (a) 4. (c) 5. (c) 6. (a) 7. (b) 8. (b)
9. (a) 10. (c)
True or False
1. (T) 2. (F) 3. (T) 4. (F) 5. (T) 6. (F)
Fill in the blanks
1. number 2. three 3. seven 4. 0,9 5. 2
Number Systems and Encoding Schemes 67

