Page 67 - computer science (868) class 11
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3.  Let, P : I live in Kolkata.
                            Q : I love sweets. Then q' → p is ………………… .
                       a.  If I live in Kolkata then I love sweets.
                       b.  If I do not live in Kolkata then I do not love sweets.
                       c.  If I do not love sweets then I live in Kolkata.
                       d.  If I love sweets then I live in Kolkata.
                    4.  A + B = 1 is a ………………… .
                       a.  Tautology                                   b.  Contradiction
                       c.  Contingency                                 d.  Converse
                    5.  Contrapositive of a conditional a' → b' is ………………… .
                       a.  a  → b                                      b.  b → a
                       c.  b' → a'                                     d.  a' ∨ b'
                    6.  The NAND gate output will be high, if the two inputs are ………………… .
                       a.  0, 0                                        b.  0, 1
                       c.  1, 0                                        d.  1, 1

                    7.  How many AND gates are required to realise Y = A.B.C + D.E + F?
                       a.  4                                           b.  5
                       c.  3                                           d.  2
                    8.  A full adder logic circuit will have ………………… .
                       a.  two inputs and one output                   b.  three inputs and three outputs
                       c.  three inputs and two outputs                d.  two inputs and two outputs
                    9.  Which of the following is true for XOR gate?
                       a.  It results in 1 when all inputs are 1.      b.  It results in 1 for an odd number of 1 as input.
                       c.  It results in 1 for an even number of 1 as input.   d.  It results in 1 for any input as 1.
                    10.  Which of the following are the fundamental gates?
                       a.  NAND, NOR                                   b.  XOR, XNOR
                       c.  AND, OR                                     d.  NOT, NOR
                  Answers
                    1.  d      2.  d     3.  c     4.  a    5.  b     6.  a     7.  d     8.  c     9.  b     10.  c

                 B.  Fill in the blanks:

                    1.  The Boolean expression of two variables NAND gate represented by variables A and B is ………………… .
                    2.  The gate produced by inverting the XOR gate is ………………… .
                    3.  ………………… NAND gates in series is equivalent to AND gate.
                    4.  NAND and NOR gates are called  ………………… gates.
                    5.  ………………… is a unary gate.
                    6.  A → B is equivalent to ………………… .
                    7.  (A → B).(B → A) is an expression for ………………… .
                    8.  Compound propositions are joined by ………………… .
                    9.  A.0 = 0 is an example of ………………… .
                    10.  The sum term of a half adder is equal to two variables ………………… gate.

                   Answers
                   1.  (A.B)'           2.  XNOR                3.  Two             4.  universal              5.  NOT
                   6.  A'+B             7.  biconditional           8.  connectives           9.  contradiction   10.  XOR



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