Page 91 - Computer science 868 Class 12
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9.  There are ………………… output lines in hexadecimal to binary encoder.
                       a.  16                                          b.  8
                       c.  4                                           d.  2
                   10.  Which is not a correct MUX?
                       a.  4 × 1 MUX                                   b.  8 × 1 MUX
                       c. 16 × 1 MUX                                   d.  12 × 1 MUX
                 B.  Fill in the blanks:
                    1.  The boolean expression of a two-variable XNOR gate represented by variables A and B is ………………… .
                    2.  The gate produced by combining two NOR gates in series is ………………… .
                    3.  ………………… is the expression of the sum term of a half adder.
                    4.  AND, OR, NOT  are called  ………………… gates.
                    5.  XOR gate produces 1 for ………………… combinations of 1 as input.
                    6.  A 9 B is equivalent to ………………… .
                    7.  A full adder can be obtained by joining two ………………… and an OR gate.
                    8.  AND gate is 1 when ………………… its inputs are 1.
                    9.  When the antecedent and consequent of a proposition is interchanged, the resulting proposition is called ………………… .
                    10.   The carry term of a full adder is ………………… .
                 C.  Answer the following questions:
                    1.  Distinguish between:
                        (i)  NAND and NOR gate                          (ii)  Encoder and Decoder
                        (iii)  Decoder and Multiplexer                 (iv)  AND gate and OR gate
                       (v)  Half adder and Full adder
                    2.  A logical circuit is given:

                                                       ?1?
                         A
                                                                    ?3?
                                                                              ?4?
                                                     ?2?
                         B


                         C

                       Write the Boolean expression for:
                       (i) ?1?               (ii)  ?2?                (iii)  ?3?              (iv)  ?4?
                    3.  In the given logic circuit, write the Boolean expression for:
                       (i) ?1?               (ii) ?2?                 (iii)  ?3?

                                                                           ?1?
                                                A                                       ?3?





                                                B                                   ?2?



                                                C

                     4.  (i)  Draw the truth table and logic gate diagram for an Octal to Binary encoder.
                       (ii)  What is Multiplexer? State an application of a Multiplexer. Also, draw the logic diagram of a 4 × 1 Multiplexer.
                        (iii)  Define Half Adders. Draw the circuit diagram and the truth table for a Half Adder.      [ISC 2015]



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