ISC Computer Science 2016 Class-12 Previous Year Question Paper Solved for practice. Step by step Solutions with Questions of Part-1 and Part-2 (Section-A,B and C). By the practice of Computer Science 2016 Class-12 Solved Previous Year Question Paper you can get the idea of solving.

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## ISC Computer Science 2016 Class-12 Previous Year Question Paper Solved

Part-I

Section-A of Part-II

Section-B of Part-II

Section-C of Part-II

Maximum Marks: 70
Time allowed: 3 hours

• 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 rest of the answer.
• The intended marks for questions or parts of questions are given in brackets [ ].

Part – I (20 Marks)

### ISC Computer Science 2016 Class-12 Previous Year Question Paper Solved

While answering questions in this Part, indicate briefly your working and reasoning, wherever required.

Question 1.
(a) State Involution law and prove it with the help of a truth table.  (b) Show that X ∨ ~ (Y ∧ X) is a tautology.  (c) Find the dual of  YX + X’ + 1 = 1
(d) Write the maxterm and minterm, when the inputs are A = 0, B = 1, C = 1 and D = 0.  (e) Draw the logic circuit of a NAND gate using NOR gates only.  Answer 1:   Question 2.
(a) Define the term fall through the condition with reference to switch () case.  (b) Convert the following infix expression into postfix form: 
A + B / C * (D/E * F)
(c) A matrix A[m] [n] is stored with each element requiring 4 bytes of storage. If the base address at A  is 1500 and the address at A   is 1608, determine the number of rows of the matrix when the matrix is stored in Column Major Wise.  (d) From the class declaration given below, state the nature of the identifiers A, B, C and D:  class A extends B implements C, D
(a) Fall through is prevented with a break keyword at the end of the matching body, which exits execution of the switch block, but this can cause bugs due to unintentional fall through if the programmer forgets to insert break statement.

(b) A + B/C * (D/E * F) = A + B/C (D/EF*)*
= AB/C+ (D/EF*)*
= AB/C + DEF*/*

(c) A [m] [n] i = 4, B = 1500
j = 5, w = 4
B  [i][j] = 1608 Class A is the superclass of B which in turn is the superclass of subclass C and D

(e) In iteration, the statement is executed repeatedly using the same memory space which is allocated once.
In recursion, the statement is executed repeatedly by invoking the same function within itself and for each recursive call, a fresh memory is allocated. The recursive function runs slower as compared to iteration.

Question 3.
The following function Check() is a part of some class. What will the function Check() return when the values of both ‘m’ and ‘n’ is equal to 5? Show the dry run/working. 

```int Check (int m, int n)
{
if(n = = 1)
return - m --;
else
return + + m + Check (m, -- n);
}```

The value of m and n are 5 which is not equal to 1. It is, for this reason, the first if block is not executed as a result it will jump to the else part where the value of m will be 6 and n will be 4. As m is having Pre Increment operator so the value of m is changed to 6 and the value of n to 4 as it is the Pre Decrement operator.

Part- II (50 Marks)

Answer six questions in this part, choosing two questions from Section A, two from Section B and two from Section C.

Section – A

### Previous Year Question Paper Solved ISC Computer Science 2016 Class-12

Question 4.
(a) Given the Boolean function F (A, B, C, D) = Σ (1, 3, 5, 7, 8, 9, 10, 11, 14, 15).
(i) Reduce the above expression by using 4-variable Karnaugh map, showing the various groups (i.e. octal, quads and pairs).  (ii) Draw the logic gate diagram for the reduced expression. Assume that the variables and their complements are available as inputs.  (b) Given the Boolean function:
F (A, B, C, D) = π (4, 6, 7, 10, 11, 12, 14, 15)
(i) Reduce the above expression by using the 4-variable Karnaugh map, showing the various groups (i.e., octal, quads and pairs).  (ii) Draw the logic gate diagram for the reduced expression. Assume that the variables and their complements are available as inputs.  Answer 4:
(a) (i) F (A, B, C, D) = Σ (1, 3, 5, 7, 8, 9, 10, 11, 14, 15)    Question 5.
(a) What is a decoder? Draw the logic diagram for a binary to octal (3 to 8) decoder.  (b) How is a half adder different from a full adder? Draw the truth table and derive the SUM and CARRY expression for a full adder. Also, draw the logic diagram for a full adder.  (c) State whether the following expression is a Tautology, Contradiction or a Contingency, with the help of a truth table:
(a) A decoder is a circuit which converts the binary number into equivalent decimal form. In a decoder, if there are 3 input lines it will be capable of producing 8 distinct output one for each of the states. Half Adder: It is a logic circuit that adds two bits. It produces the outputs; SUM and CARRY. Full Adder: It is a logical circuit that adds three bits. It produces two outputs; SUM and CARRY    Question 6.
(a) A passenger is allotted a window seat in an aircraft if he/she satisfies the criteria given below:  The passenger is below 15 years and is accompanied by an adult.
or
The passenger is a lady and is not accompanied by an adult.
or
The passenger is not below 15 years but is travelling for the first time.
The inputs are:

 Inputs A The passenger is below 15 years age. C The passenger is accompanied by an adult. L The passenger is a lady. F The passenger is travelling for the first time.

(In all the above cases 1 indicates yes and 0 indicates no).
Output: W – Denotes the passenger is allotted a window seat (1 indicates yes and 0 indicates no)
Draw the truth table for the inputs and outputs given above and write the SOP expression for W(A, C, L, F).
(b) State the complement properties. Find the complement of the following Boolean expression using De Morgan’s law:  AB’ + A’ + BC
(c) Differentiate between Canonical form and Cardinal form of expression.  Answer 6:
(a) From the above, we have four inputs and one output W. The truth table for the given variables is as shown below:  Read Next 👇 Click on Page Number Given Below 👇