PLUS ONE COMPUTER SCIENCE
First Year Computer Science Previous Questions Chapter wise ..
Chapter 2. Data Representation and Boolean Algebra
1. NAND gate is known as universal gate because it can be connected to other NAND gates to generate any logic function. Show how will you connect NAND gates to produce OR gate, AND gate and inverter.
2. Represent the following integers in sign and magnitude form, 1’s complement from and 2’s complement form by using eight bits.
a) +25
b) –30
3. Briefly explain any three methods of representing characters in computer memory.
4. The number (158)10 can be represented in Hexadecimal number system as ………..
5. Represent –38 in 2’s complement form.
6. Draw the logic circuit for the Boolean expression: (A+ BC )+ AB
7. Using algebraic method, prove that Y . Z + Y . Z+Y .Z + Y = 1
8. Which one of the following file extensions is different from others?
a) WAV
b) MP3
c) PNG
d) MIDI
9. Perform the following number conversions:
a) (110111011.11011)2 = ( ………… )8
b) (128.25)10 = ( ………… )8
10. With the help of a neat circuit diagram, prove that NAND gate is a universal gate.
11. 1’s compliment of the binary number 110111 is ______. (Hint: Use 8 bit form)
8bit form: 00110111
1's compliment form: 11001000
12. Express the integer number –39 in sign & magnitude representation.
13. Following are the numbers in various number systems. Two of the numbers are same. Identify them:
(a) (310)8
(b) (1010010)2
(c) (C8)16
(d) (201)10
14. Consider the following Boolean expression: (Bl +A)l = B. Al Identify the law behind the above expression and prove it using algebraic method.
15. Computers use a fixed number of bits to represent data which could be a number, a character, image, sound, video etc. Explain the various methods used to represent characters in memory.
16. Draw the logic circuit for the function: f(a,b,c,d)=a.b.c+a bar.b+a.b bar+a.b.cbar
17. Prove algebraically: x.(y.z) = x.y + x.z
18. Fill in the blanks:
(a) (0.625)10 = ( _______ )2
(b) (380)10 = ( _______ )16
(c) (437)8 = ( _______ )2
19. What do you mean by universal gates? Which gates are called universal gates? Draw their symbols.
The NAND and NOR gates are called universal gates. A universal gate is a gate which can implement any Boolean function without using any other gate type.
NAND: It is an inverted AND operation. NAND gate is an inverted AND gate.
NOR: It is an inverted OR operation. NOR gate is an inverted OR gate.
20. Construct a logical circuit for the Boolean expression
a . b + a .
b . Also write the truth
table.
