COMPUTER SCIENCE

-------------------------------------------------------------------------------------------------------------------------------
ISC Specimen Question Paper
6
COMPUTER SCIENCE
Paper – 1
(THEORY)
Three 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 seven questions from Part-II, choosing three 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
Answer all questions
While answering questions in this Part, indicate briefly your working and reasoning,
wherever required.
Question 1
(a) Draw the truth table to prove the proportional logic expression. [2]
a<=>b = (a => b) . (b => a)
(b) Determine if following wff is valid, satisfiable or unsatisfiable: [2]
(p -> q) => [~q -> (~p ^ ~q)]
(c) Differentiate between a tautology and a contradiction. [2]
(d) Convert the following expression F(X,Y,Z) = XY+Y’Z into minterms. [2]
(e) Minimise F = AB + (AC)’ +AB’C using Boolean laws. [2]
Question 2
(a) What is dynamic binding? [2]
(b) Convert the following infix notation to postfix : [2]
A*(B/C)/((E*F)+G)
(c) Define the terms Best-Case and Average-Case in complexities. [2]
(d) Each element of an array arr[15][20] requires ‘W’ bytes of storage. If the address of
arr[6][8] is 4580 and the Base Address at arr[1][1] is 4000 , find the width ‘W’ of each
cell in the array arr[ ][ ] when the array is stored as Column Major Wise. [2]
(e) Define an abstract class. [2]


-------------------------------------------------------------------------------------------------------------------------------
ISC Specimen Question Paper
7
Question 3
(a) The following function comb( ) and combi( ) are a part of some class. Give the
output when the function combi( ) is called. Show the dry run/working. [5]
void combi ( )
{
for (int i=0 ; i<5 ; i++)
{
for (int j=0 ; i<i+1 ; j++)
System.out.print ( ” “ + comb ( i , j ) );
System.out.println ( );
}
}
long comb (int n , int k)
{
long c = 1;
for (int i = 1; i<=k ; i++ , n--)
c= c*n/i;
return c;
}
(b) The following function find( ) and perform ( ) are part of some class. Show the dry run /
working:
int find ( int n, int p)
{
if ( n = = 0 )
return p;
else
return find ( p % n , n );
}
void perform ( int m )
{
int q = 14;
int x = find ( q++, ++m);
System.out.println(x);
}
(i) What will the function find (12, 8) return? [2]
(ii) What will be the output of the function perform ( ) when the value of m is 20. [2]
(iii) In one line state what the function find ( ) is doing, apart from recursion. [1]


PART – II
Answer seven questions in this part, choosing three questions from
Section A, two from Section B and two from Section C.
SECTION - A
Answer any three questions
Question 4
(a) Given F(A,B,C,D) = Σ (0,2, 6,8,10,11,14,15)
(i) Reduce the above expression by using 4 - Variable K-Map , showing the various
groups (i.e octal , quads and pairs). [4]
(ii) Draw the Logic gate diagram of the reduced expression using NAND Gate only. [1]
(b) Given F(A,B,C,D) = π (5,7,8,10,12,14,15).
(i) Reduce the above expression by using 4 - Variable K-Map , showing the various
groups (i.e octal , quads and pairs). [4]
(ii) Draw the Logic gate diagram of the reduced expression using NOR Gate only. [1]
Question 5
(a) Draw the logic diagram and Truth table to Encode the hexadecimal lines ( A – F).
Briefly explain the working of the logic diagram. [5]
(b) Simplify the equation and draw the gate for the reduced expression.
F= A’B + AB’C + A [2]
(c) Define maxterms and minterms. Give one example of each. [3]
Question 6
(a) Draw a truth table with a 3 input combination which outputs 1 if there are odd number
of 0’s. Also derive an S-O-P expression for the same. Reduce the S-O-P expression
using K-map. [3]
(b) State the principal of duality. Give one example. [2]
(c) How many select lines does an 8 : 1 multiplexer have? Briefly explain the working of a
4 : 1 multiplexer. Also draw the logic diagram of a 4 : 1 multiplexer. [5]
-------------------------------------------------------------------------------------------------------------------------------


Question 7
(a) How does Half adder differ from Full adders? Draw truth table for both the adders. Also
derive expression for full adder and simplify the same. [5]
(b) From the given logic diagram :
Derive Boolean expression and also draw the truth table. [3]
(c) Verify the following :
Σ (0,2,7,6) = π (1,3,4,5) [2]
SECTION – B
Answer any two questions
Each program should be written in such a way that it clearly depicts the logic of the problem.
This can be achieved by using mnemonic names and comments in the program.
( Flowcharts and Algorithms are not required )
The programs must be written in Java
Question 8 [10]
Design a class Prime to fill an array of order [m x n] where the maximum value of both m and n
is 20, with the first [m x n]prime numbers Row wise .The details of the members of the class are
given below :
Class name : Prime
Data members /instance variables :
arr[ ][ ] : Two dimensional integer array.
r : integer to store the number of rows.
c : integer to store the number of columns.
-------------------------------------------------------------------------------------------------------------------------------


-------------------------------------------------------------------------------------------------------------------------------
ISC Specimen Question Paper
10
Member functions :
Prime( ) : to accept the size of the array .
int isprime( int p ) : return 1 if number is prime and 0 if not prime .
void fill ( ) : to fill the elements of the array with the first (m x n)
prime numbers.
void display( ) : displays the array in a matrix form.
Specify the class Prime giving details of the constructor and member functions int isprime
(int), void fill( ) and void display( ) with main( ) function to create an object and call the
function accordingly.
Question 9 [10]
Design a class Alpha which enables a word to be arranged in ascending order according to its
alphabets.
The details of the members of the class are given below :
Class name : Alpha
Data members /instance variables:
Str : to store a word
Member functions :
Alpha( ) : default constructor
void readword( ) : to accept the inputted word
void arrange ( ) : to arrange the word in alphabetical order using any
standard sorting technique.
void disp( ) : displays the word .
Specify the class Alpha giving details of the constructor and the member functions void
readword( ), void arrange( ), void disp ( ) and defining the main ( ) function to create an object
and call the function in order to execute the class by displaying the original word and the
changed word with proper message.

Question 10 [10]
The Combination function C(n , k) gives the number of different (unordered ) K – elements
Subsets that can be found in a given set of n elements. The function can be computed from the
formula:
( ) ( )
, !
! !
C n k n
k n k
=
−
Design a class Combination to implement this formula. Some of the data members and member
functions are given below.
Class name : Combination
Data members /instance variables :
n : integer number
k : integer number
Member functions :
Combination ( ) : to initialize the data members n = 0 and k = 0
void read( ) : to accept the value of the data members
int fact(int) : return the factorial of a number using recursion technique.
void compute( ) : calculate the combination value
void display( ) : to show the result
Specify the class Combination, giving details of the Constructor and member functions void
read( ), int fact(int), void compute( ) and void display( ) with the main() function to create an
object and call the member function according to enable the task .
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
ISC Specimen Question Paper
12
SECTION – C
Answer any two questions
Each Program / Algorithm should be written in such a way that it clearly depicts the logic of the
problem step wise. This can also be achieved by using pseudo codes .
(Flowcharts are not required )
Programs to be written in Java.
The Algorithm must be written in general/standard form.
Question 11 [10]
A class Personal contains employee details and another class Retire calculates the employee’s
Provident Fund and Gratuity. The details of the two classes are given below:
Class name : Personal
Data Members:
Name : stores the employee name
Pan : stores the employee PAN number
basic_pay : stores the employee basic salary (in decimals)
acc_no : stores the employee bank account number
Member functions:
Personal( …. ) : parameterized constructor to assign value to data
members
void display( ) : to display the employee details
Class name : Retire
Data Members:
Yrs : stores the employee years of service
Pf : stores the employee provident fund amount
( in decimals )
Grat : stores the employee gratuity amount ( in decimals )
Member functions:
Retire ( …. ) : parameterized constructor to assign value to data
members of both the classes.
void provident( ) : calculates the PF as (2% of the basic pay) * years of
service.
void gratuity( ) : calculates the gratuity as 12 months salary, if the
years of service is more than or equal to 10 years
else the gratuity amount is nil.
void display1( ) : Displays the employee details along with the PF
(Provident Fund ) and gratuity amount.
Specify the class Personal giving details of the constructor and member functions
void display( ). Using the concept of inheritance, specify the class Retire giving details of
constructor, and the member functions void provident( ), void gratuity( ) and the
void display1( ). The main function need not be written.


-------------------------------------------------------------------------------------------------------------------------------
ISC Specimen Question Paper
13
Question 12
Chain is an entity which can hold at the most 50 integers. The chain enables the user to add and
remove integers from both the ends i.e. front and rear. Define a class Chain with the following
details:
Class name : Chain
Data Members:
ele[ ] : the array to hold the integer elements.
cap : stores the maximum capacity of the array.
front : to point the index of the front.
rear : to point the index of the rear.
Member functions:
Chain(int max) : constructor to initialize the data cap = max, front =
rear = 0 and to create the integer array.
void pushfront(int v) : to add integers from the front index if possible else
display the message(“full from front”).
int popfront( ) : to remove the return elements from front. If array
is empty then return-999.
void pushrear(int v) : to add integers from the front index if possible else
display the message(“full from rear”).
int poprear( ) : to remove and return elements from rear. If the
array is empty then return-999.
(a) Specify the class Chain giving details of the constructor and member function void
pushfront(int), int popfront( ), void pushrear(int) and int poprear ( ).The main function
need not be written. [9]
(b) What is the common name of the entity described above? [1]


Question 13
(a) Link Lists are linear data structure . Create Algorithms for the following operations :
(i) Insertion of a Node at the beginning in a Link List. [4]
(ii) Deletion of the first Node in a Link list.
(b) Answer the following from the diagram of a Binary Tree given below:
1. Name the leaves of the tree. [1]
2. Write the path between A to G. [1]
3. State the level of node E . [1]
(c) For the given Binary Tree write the: [3]
1. Postorder Sequence.
2. Inorder Sequence.
3. Preorder Sequence.
A
B
F G
H
C
D
E
-------------------------------------------------------------------------------------------------------------------------------
ISC Specimen Question Paper
14



-------------------------------------------------------------------------------------------------------------------------------
ISC Specimen Question Paper
15
COMPUTER SCIENCE
Paper – 2
(PRACTICAL)
(Reading Time : 15 minutes)
(Planning Session AND Examination Session : Three Hours)
-------------------------------------------------------------------------------------------------------------------------------
The total time to be spent on the Planning session and the Examination session is Three hours.
After completing the Planning Session, the candidate may begin with the Examination Session.
A maximum of 90 minutes is permitted for the Planning Session.
However, if candidates finish earlier, they are to be permitted to begin the Examination Session.
(Maximum Marks : 80 )
-------------------------------------------------------------------------------------------------------------------------------
As it is a practical examination the candidate is expected to do the following :
1. Write an algorithm for the selected problem.
( Algorithm should be expressed clearly using any standard scheme such as pseudo code or in steps
which are simple enough to be obviously computable ) [10]
2. Write a program in JAVA language. The program should follow the algorithm and should be
logically and syntactically correct. [20]
3. Document the program using mnemonic names / comments, identifying and clearly describing
the choice of data types and meaning of variables. [10]
4. Code / Type the program on the computer and get a printout ( Hard Copy ). Typically, this
should be a program that compiles and runs correctly. [10]
5. Test run the program on the computer using the given sample data and get a printout of the
output in the format specified in the problem. [10]
6. Viva-Voce on the Selected Problem . [20]


-------------------------------------------------------------------------------------------------------------------------------
ISC Specimen Question Paper
16
Solve any one of the following Problems.
Question 1
Design a program which inputs a date in six digit number format i.e. 141296 . Test the validity of the
date and print the date in full form . If date is invalid then print a message as “ Invalid Date“
1. Example :
INPUT : 141296
OUTPUT : 14th December , 96
: VALID DATE
2. Example :
INPUT : 230488
OUTPUT : 23rd April , 88
: VALID DATE
3. Example :
INPUT : 300284
OUTPUT : INVALID DATE
Question 2
Write a program to fill in a two dimensional array in a circular fashion with natural numbers from 1 to N2,
given N as input.
Example : if N = 4, N2 = 16, then the array will be :
1 2 3 4
12 13 14 5
11 16 15 6
10 9 8 7
Question 3
Accept a paragraph of text consisting of sentences that are terminated by either “.”, “,”, “!” or a “?”
followed by a space. Assume that there can be a maximum of 05 sentences in a paragraph.
Design a program to perform the following :
(a) Arrange the sentences in alphabetical order of words, sentence by sentence.
(b) Separate the words which begin with a vowel.
Sample data 1:
INPUT: HELLO ! HOW ARE YOU ? WHEN ARE YOU COMING ? HOPE TO SEE YOU
SOON.
OUTPUT: HELLO ! ARE HOW YOU ? ARE COMING WHEN YOU ? HOPE SEE SOON
TO YOU.
VOWELS: ARE
Sample data 2 :
INPUT : THE QUICK BROWN FOX JUMPED OVER THE LAZY DOG.
OUTPUT : BROWN DOG FOX JUMPED LAZY OVER QUICK THE THE.
VOWELS: OVER


PHYSICS
Paper – 1
(THEORY)
(Three 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 and six questions from Part II, choosing two questions
from each of the Sections A, B and C.
All working, including rough work, should be done on the same sheet as, and adjacent to,
the rest of the answer.
The intended marks for questions or parts of questions are given in brackets [ ].
(Material to be supplied: Log tables including Trigonometric functions)
A list of useful physical constants is given at the end of this paper.
-------------------------------------------------------------------------------------------------------------------------------
PART I
Answer all questions
Question 1 [5]
A. Answer all questions by choosing the correct option A, B, C or D.
(i) Three identical point charges, each of Q Coulomb, are kept at the three vertices of an equilateral
triangle having each side = a. [See figure 1]. Electro-static potential energy of the system is:
Q
Q Q
a
Figure 1
(A)
2
0
1
4
Q
π ∈ a
(B)
2
0
1 3
4
Q
π ∈ a
(C)
2
2
0
1 3
4
Q
π ∈ a
(D)
2
2
0
1
4
Q
π ∈ a
-------------------------------------------------------------------------------------------------------------------------------

(ii) Four cells E1 , E2 , E3 and E4 are connected as shown in Figure 2. Emf of the battery so formed is:
E1 E2 E3
E4
2V 2V 2V
6V
+ -
Figure 2
(A) 6V (B) 12V (C) 4V (D) Zero
(iii)
A 50 Ω non-inductive resistor is connected to a source which generates an emf e which is given
by
e = 200 Sin (120 π t) Volt. Peak value of current flowing through the resistor is:
(A) 0.25 A (B) 2.5 A (C) 4.0 A (D) 4 2 A
(iv) A thin converging lens of focal length 25 cm is kept in contact with a thin diverging lens of focal
length 20 cm. Focal length of the combination is:
(A) + 100 cm (B) -100 cm (C) 45 cm (D) 5 cm
(v) Photo electric threshold wavelength of a certain metal is 198 nm. Its work function is:
(A) 1×10−18J (B) 1×10−19J (C) 1×10−16J (D) 1×10−17J
B. Answer all questions briefly and to the point: [15]
(i) An oil drop weighing 1 × 10-15 N and carrying a charge of 8 × 10-19 C is found to remain at rest
in a uniform electric field of intensity ‘E’. Find ‘E’.
(ii) Which conservation principle is involved in Kirchoff’s second law?
(iii) State any one difference between Joule effect and Peltier’s effect.
-------------------------------------------------------------------------------------------------------------------------------

(iv) Two thin, infinitely long conductors, X and Y, carrying currents I1 and I2 are kept
parallel to each other, at a distance ‘a’, in vacuum [See figure 3].
X
Y
I1
I2
a
Figure 3
How much force acts on a 1m span of wire Y due to current flowing through X?
(v) Alternating current I flowing through a device lags behind the potential difference
V across it by 90° or
2
π
radian. Is this electrical device a resistor, an inductor or a
capacitor?
(vi) An electro magnetic wave has a frequency of 1 MHz. On which part of the electro
magnetic spectrum does this wave lie?
(vii) What kind of source produces a cylindrical wave front?
(viii) Plot a labelled graph showing variation of relative intensity with respect to
distance, in a single slit diffraction experiment.
(ix) State any one method by which chromatic aberration produced by a convex lens
can be minimized.
(x) Give any one reason why giant telescopes all over the world are of reflecting type.
(xi) Figure 4 below is a graph showing variation of relative intensity I of X rays Vs its
wavelength λ , when X ray tube is operated at a tube potential of 20 KV.
I
λm λ
Figure 4
Redraw this graph in your answer book and on same axes, draw another such
graph when tube potential is raised to 30 KV.
-------------------------------------------------------------------------------------------------------------------------------

(xii) Write down the relation between mean life τ of a radioactive substance and its half
life T½ .
(xiii) According to the modern view, matter and energy are inter-convertible. Give one
example where energy is converted to matter.
(xvi) Draw graphs to show input and output voltages of an ideal amplifier.
(xv) Write down the truth table of a NAND gate.
PART II
Answer six questions in this part, choosing two questions
from each of the Sections A, B and C.
SECTION A
(Answer any two questions)
Question 2
(a) Figure 5 (a) below shows a parallel plate air capacitor whose capacitance is 2μ F.
A
I
R
A
I
R
A
I
R
M
d N
4 cm
4 cm
t
∈r=10
Figure 5 (a) Figure 5 (b)
A dielectric slab MN of thickness t = 2 cm and having dielectric constant (relative
permittivity) = 10 is now introduced between the two plates (See figure 5 (b))
Find the new capacitance of the system.
[4]
(b) Using Gauss’ Theorem, calculate intensity of electric field at a point at a radial
distance of 3 cm from an infinite line charge having linear charge density of 5 × 10-6
Cm-1.
(Statement of Gauss’ Theorem or derivation not required).
[2]
(c) What is meant by temperature coefficient of resistance? Write down Ohm’s Law in
vector form, stating the meaning of every symbol used.
[3]
-------------------------------------------------------------------------------------------------------------------------------

Question 3
(a) Draw a labelled diagram of a balanced Wheat Stone bridge. Using either Ohm’s Law
or Kirchoffs’ Laws, obtain the relation between four resistors forming the bridge.
[3]
(b) Figure 6 below shows a potentiometer circuit. When the jockey is pressed on the
slide wire AB at a point C such that AC = 2.9m, the galvanometer ‘G’ shows no
deflection. Find the emf of the cell X.
G
A B
X
D R
C
4V, 2Ω 10Ω
5m, 20Ω
Figure 6
[Slide wire AB is 5m long and has a resistance of 20Ω.]
[3]
(c) Figure 7 below shows three resistors: R1 = 10Ω , R2 = 20Ω and R3 = 90Ω. When a
current I enters the circuit, heating power developed in R1 is found to be 90 W.
Calculate the heating power developed in R3 .
I
C
A B
D
I
R3
R1 R2
Figure 7
[3]
-------------------------------------------------------------------------------------------------------------------------------

Q
uestion 4
(a) Using Ampere’s circuital law, obtain an expression for magnetic flux density ‘B’ at a
point ‘P’near an infinitely long straight conductor carrying a current ‘I’.
[3]
(b)
Show graphically how a d.c current flowing through an LR circuit varies with time
when the key is put (i) on (ii) off. What is meant by time constant of an LR circuit
?
[3]
(c)
A 2
(25)μ F
π
capacitor ‘C’ and a 50 Ω resistor ‘R’ are connected in series to a 220V,
50Hz a.c supply. It is desired to have a current of 2A in phase with supply voltage.
Find the value/s of additional component/s to be connected in series with C and R.
[3]
SECTION B
(Answer any two questions)
Que stion 5
(a) Which electro-magnetic wave is longer than a light wave but shorter than a
micro-wave? How can it be detected? Name only one detector.
[2]
(b) In Young’s double slit experiment, what is the effect of the following changes on the
interference pattern:
(i) Distance between the two slits is decreased.
(ii) One of the slits is covered with a thin mica sheet.
(iii) Monochromatic light is replaced by white light.
[3]
(c) Ordinary light i.e. unpolarized light is incident on a glass slab (refractive index = 1.6)
at a polarizing angle θ p as shown in figure 8 below.
GLASS
R2
R1
θp
Figure 8
(i) Find the value of angle θ p.
(ii) What is the angle between the reflected ray R1 and the refracted ray R2 ?
(iii) What is the difference between the incident light and the reflected light, as
far as their electric vectors are concerned?
[3]
-------------------------------------------------------------------------------------------------------------------------------

Question 6
(a) An air bubble ‘A’ is trapped inside a glass sphere of radius CP = 10 cm at a distance
of 4.0 cm from its centre ‘C’. Where does it appear to an observer O (See figure 9)
who is looking at it along the diameter from the side to which it is nearest?
(Refractive Index of glass = 1.5)
C
GLASS
(μ = 15)
A P
AIR
Observer
Figure 9
[3]
(b) A beam of light converges to a point X. A convex lens of focal length 30 cm is now
introduced in its path in order to intercept the rays, at a distance of 30 cm from X.
The rays of light now meet at a point Y. Draw the ray diagram showing the position
of X & Y and calculate the distance XY.
[3]
(c) What are Fraunhoffer lines? Explain how they are formed. [2]
Question 7
(a) Explain the statement: “Angular magnification of an astronomical telescope in normal
adjustment is 20”. What is meant by resolving power of a telescope?
[3]
(b) Draw a labelled ray diagram of an image formed by a Compound Microscope in
normal use. Write down an expression for its magnifying power in terms of focal
lengths of the two lenses used.
[3]
(c) When a narrow and parallel beam of monochromatic light is incident normally on a
rectangular slit of width 1 × 10-6m, angular width of central maxima in the diffracted
light was found to be 60°. Find the wave length of the incident light.
[2]
-------------------------------------------------------------------------------------------------------------------------------

SECTION C
(Answer any two questions from the following)
Question 8
(a) In Millikan’s oil drop experiment, charge q on an oil drop is given by
1 1 2
q= K V (V -V )
E
.
(i) What is the difference between V1 and V2?
(ii) What is meant by the term: “Quantisation of charge”?
[3]
(b) When UV radiation of wavelength 198.0 nm is incident on a Caesium photo cell, a
negative potential difference of 4.2V has to be applied to just cut off the
photo-current. Calculate threshold frequency for metal Caesium.
[3]
(c) (i) Find angular momentum of an electron in Bohr’s III orbit.
(ii) What is the radius of IIIrd orbit of an electron in hydrogen atom?
[2]
Question 9
(a)
Explain the terms:
(i) Mass defect.
(ii) Binding energy of a nucleus.
[2]
(b) (i) In Nuclear Physics, what is the use of a cyclotron ?
(ii) In a nuclear reactor, what is the function of a moderator ?
[2]
(c) (i) State Mosley’s Law.
(ii) What is a neutrino?
(iii) Half life of a certain radio active element is 6 hours. If you start with 32g of
this element, how much of it would disintegrate in one day?
[4]
-------------------------------------------------------------------------------------------------------------------------------

Question 10
(a) Draw labelled energy band diagram for each of the following:
(i) A semi-conductor.
(ii) An insulator.
(iii) A good conductor.
[3]
(b) Draw a labelled circuit diagram of a full wave rectifier using two junction diodes.
You must show clearly where input voltage is applied and where output voltage is
taken.
[3]
(c) Show how an OR gate can be obtained using NAND gates. [2]
USEFUL CONSTANTS
1. Speed of light in vacuum : c = 3 × 108 ms-1
2. Planck’s constant : h = 6.6 × 10-34 Js
3. Constant of proportionality
for Coulomb’s Law
:
1
4 ο πε
= 9 × 109 mF-1
4. Bohr radius : aο = 5.3 × 10-11m
5. Charge of a proton : e = 1.6 × 10-19C
6. Constant of proportionality
for Biot Savart Law
:
4
ο μ
π
= 10-7 Hm-1
-------------------------------------------------------------------------------------------------------------------------------
ISC Specimen Question Paper
25