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# Logical gates and Boolean Laws questions

## Short answer questions (1 mark)

### Fill in the blanks:

1. A __________ statement returns either True or False value.
2. The logical values can be stored in ______________.
3. A __________ represents a Boolean function with all the input and output in tabular form.
4. The only boolean function which operate on a single input variable is ____________.
5. The _____________ is a boolean operation which perform multiplication.
6. The ___________ is a boolean operation which perform addition.
7. The boolean expression evaluated from ________ to ___________.
8. The _________ operator has high (top) priority in boolean statement evaluation.
9. The __________ is a graphical representation of turth table.
10. The __________ gate produces the reverse result of AND gate.

1. boolean
2. logical variables or constants
3. Truth Table
4. Not
5. AND
6. OR
7. left, right
8. NOT
9. Logical Gate
10. NAND

### MCQs:

• When the result of any boolean statement is always 1 is known as ___________.
1. True
2. Tautology/
3. Fallacy
4. False
• When the result of any boolean statement is always 0 is known as ______________.
1. True
2. Tautology
3. Fallacy
4. False
• The logical operations can be carried out by which of the following?
1. Values and Variables
2. Functions and Laws
3. Operators and Operands
4. None of these
• To denote NOT operation which of the following symbols is used?
1. bar
2. dot
3. plus
4. asterisk
• The dot symbol is used to represent which of the following operation?
1. AND
2. OR
3. NOT
4. NAND
• Which of the following are logical statements:
1. The Indian cricket team is a world champion in 2011.
2. What are the parts of the boolean function?
3. There are three types of boolean operators.
4. The NOT function can be operated on more than one Boolean function.
• Which of the following gate is also known as an invertor
1. AND
2. OR
3. NOT
4. NAND
• Which of the following gate returns a true result if both inputs are true otherwise false.
1. AND
2. OR
3. NOT
4. None of the above
• Which gate can be written like A & B
1. AND
2. OR
3. NOT
4. XOR
• Which gate returns true if both inputs are similar otherwise false.
1. NAND
2. NOR
3. XOR
4. None of the above

1. b.Tautology      2. c. Fallcy      3. c. Operators and Operands      4. a. bar    5. a. AND

6. a and d             7. c. NOT        8. a. AND                     9. a. AND        10. XOR

## Descriptive questions:(2/3 marks)

1. Prepare the truth table for a.  X+(X.Y)   b. X.(X+Y)     c. X + Y    d. (X.Y) + (Y.X)
2. Write rules for preparing the truth table.
3. Explain the following gates with an example:
1. AND
2. OR
3. NAND
4. NOR
5. XOR
4. Name following law and verify them using a truth table:
1. x + x’ = 1
2. x + y = y + x
3. x + (y + z ) = (x + y ) + z
4. x + xy = x
5. (x + y)’ = x’.y’
5. Draw logical circuits for following:
1. Y = ab + bc + ca
2. Y = (a+b)’ . (a+b)
3. Y = a’.b’ + (a.b)’
6. Prove DeMorgan’s law using truth table.
7. Draw the logic circuit of boolean expression using NAND gate: (A.B)+ (C.D)
8. Represent the boolean expression A’B+B’C using the NAND gate.
9. Draw the logical circuit of F(x,y,z) = (x + y’) (y + z’) using NOR gate.
10. State and verify involution law.