Page 672 - Computer science 868 Class 12
P. 672

COMPUTER SCIENCE


                                      SAMPLE PAPER (UNSOLVED)

                                                             (THEORY)

                                       (Candidates are allowed additional 15 minutes for only reading the paper.
                                                  They must NOT start writing during this time).
                                        Answer all questions in Part I (compulsory) and six questions from Part-II,
                                           choosing two questions from Section-A, two from Section-B and
                                                           two from Section-C.
                                       All working, including rough work, should be done on the same sheet as the
                                      The intended marks for questions or parts of questions are given in brackets [ ].


                                                           PART I (20 Marks)
                                                          Answer all questions.
                                 While answering questions in this Part, indicate briefly your working and reasoning,
                                                           wherever required.
              Question 1.
                    (i)  Absorption law states that:                                                                [1]
                       (a)  A • ( A' + B) = A              (b)  A + ( A • B)  = A
                       (c)  Both (a) and (b)               (d)  A • ( B + C ) = A • B   +  A • C
                   (ii)  Assertion:  A=0 B=1 C=0 and D=1 and minterm is  A'•B•C'•D
                      Reason: The final sum term must be 0 so A and C are complemented.                             [1]
                       Which one of the following options is correct?
                       (a)  Both Assertion and Reason are true, and Reason is the correct explanation for Assertion.
                       (b)  Both Assertion and Reason are true, but Reason is not the correct explanation for Assertion.
                       (c)  Assertion is true and Reason is false.
                       (d)  Assertion is false and Reason is true.
                   (iii)  According to the Principle of duality, the Boolean equation (P + Q') • R • 1 = P • R + Q' • R will be equivalent to:
                       (a)  P • Q' + R + 1 = (P + R) • (Q' + R)   (b)  P • Q' + R + 0 = (P + R) • (Q' + R)
                       (c)  P' • Q + R + 1 = (P' • R') • (Q + R')   (d)  P • Q' + R • 0 = (P + R) • (Q' + R)        [1]
                   (iv)  The complement of the Boolean expression (X • Y)′ + Z′ is:                                 [1]
                       (a)  (X + Y) • Z  (b)  X • Y • Z
                       (c)  (X' + Y') • Z' (d)  (X' + Y') • Z
                   (v)  The equivalent of  P ∧ Q  ˅ ∼ P ˄ ∼ Q  will be:                                             [1]
                       (a)  ( ( P ˄ Q ) ∨ ~ P ) ˄ ~ Q      (b)  ( P ˄ Q  ) ∨ (  ~ P  ˄ ~ Q )
                       (c)  P ˄ ( Q ∨ ~ P )  ˄  ~ Q        (d)  P ˄ ( Q ∨  (~ P  ˄  ~ Q ) )
                   (vi)  Assertion: Boolean algebra and Binary number system are different from each other.
                      Reason: There are some basic operations like AND, OR and NOT which are performed only in Boolean algebra.
                       (a)  Both Assertion and Reason are true, and Reason is the correct explanation for Assertion.
                       (b)  Both Assertion and Reason are true, but Reason is not the correct explanation for Assertion.
                       (c)  Assertion is true and Reason is false.
                       (d)  Assertion is false and Reason is true.                                                  [1]
                  (vii)  What is the relevance of the keyword static for a data member of a class                   [1]
                  (viii)  State any one purpose of using interfaces in Java programming.                            [1]
                   (ix)  Define Canonical form of an expression with respect to its Cardinal form.                  [1]
                   (x)  State any one application each of half adder and  full adder.                               [1]




                670670  Touchpad Computer Science-XII
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