Switching Theory and Logic Design Mid - I, February - 2012

1.The minimum number of bits required to represent negative numbers in the range of -1 to -11 using 2’s complement arithmetic is
  • 2
  • 3
  • 4
  • 5
Answer: D
2.The following code is not a BCD code.
  • Gray code
  • Xs-3 code
  • 8421 code
  • All of these
Answer: A
3.A 15-bit hamming code requires
  • 4 parity bits
  • 5 parity bits
  • 15 parity bits
  • 7 parity bits
Answer: A
4.The logic expression (A B) + (~A ~B) can be implemented by giving the inputs A and B to a two-input
  • NOR gate
  • NAND gate
  • X-OR gate
  • X-NOR gate
Answer: C
5.Which of the following Boolean algebraic expressions is incorrect?
  • A+(~A)B=A+B
  • A+AB=B
  • (A+B)(A+C)=A+BC
  • (A+~B)(A+B)=A
Answer: B
6.If sqrt(41)=5,the base(radix) of the number system is
  • 5
  • 6
  • 7
  • 8
Answer: B
7.The hexadecimal number system is used in digital computers and digital systems to
  • Perform arithmetic operations
  • Perform logic operations
  • Perform arithmetic and logic operations
  • Input binary data into the system
Answer: D
8.The logic expression A(~B) + (~A)B can be implemented by giving inputs A and B to a two-input
  • NOR gate
  • NAND gate
  • X-OR gate
  • X-NOR gate
Answer: C
9.A gate is enabled when its enable input is at logic 0. The gate is
  • NOR
  • AND
  • NAND
  • None of these
Answer: A
10.The output of a logic gate is 1 , when all its inputs are at logic 0.The gate is either
  • a NOR or an X-NOR
  • a NAND or an X-OR
  • an OR or an X-NOR
  • an AND or an X-OR
Answer: A
11.In b’s complement method, the carry is ______ and in(b-1)’s complement method the carry is _______
Answer: Ignored, add to the LSD
12.The MSB of a binary number has a weight of 512,the number consists of _________ bits.
Answer: 10 bits
13.__________ are codes which represent letters of the alphabets and decimal numbers as
a sequence of 0s and 1s.
Answer: Alpha numeric codes
14.The interconnection of gates to perform a variety of logical operations is called ___________
Answer: Logic design
15.The NOR gate can function as a NOT gate if _______________
Answer: All inputs are connected together
16.The implicants which will definitely occur in the final expression are called _____________________.
Answer: Essential prime implicants
17.The prime implicant mode of a bunch of 0s is called a __________________________.
Answer: False prime implicant
18.______________ is a process of converting familiar numbers or symbols into a coded format.
Answer: Encoding
19.A decoder with 64 output lines has _____ select lines.
Answer: Six
20.A decimal – to – BCD encoder is a ________ line to ____ line encoder.
Answer: 10 , 4