Question 1

Question 1(i)Consider the below picture and choose the correct statement from the following:Polygon is the object and the pictures are classesBoth polygon and the pictures are classesPolygon is the class and the pictures are objectsBoth polygon and the pictures are objects

Accepted Answer

Polygon is the class and the pictures are objectsReason — In object-oriented programming (OOP), a class is a blueprint or template that defines the properties and behaviours (methods) of objects. An object is an instance of a class that holds specific data defined by the class.In this case:Polygon represents the class because it defines the general structure, properties, and methods common to all polygons (e.g., sides, vertices, perimeter calculation).The pictures are specific examples or instances of polygons, such as triangles, parallelogram, or pentagons, making them objects created from the Polygon class.

Question 2

Question 1(vii)if (a>b&&b>c) then largest number is:bcawrong expression

Accepted Answer

aReason — The && (Logical AND) operator in Java is used to combine two boolean expressions. It returns true only if both expressions are true. If either of the expressions is false, the entire condition becomes false.The condition if (a > b && b > c) checks two expressions:a > b – Checks if a is greater than b.b > c – Checks if b is greater than c.Since both conditions must be true (due to the && operator), the logical sequence becomes:a > b > cIn this sequence:a is the largest number because it is greater than both b and c.

Question 3

Question 1(viii)What is the output of Math.ceil(5.4)+Math.ceil(4.5)?10.011.012.09.0

Accepted Answer

11.0Reason — The method Math.ceil(double value) in Java rounds up a decimal number to the next highest integer, regardless of the fractional part.Breakdown of the Expression:Math.ceil(5.4):5.4 is rounded up to 6.0.Math.ceil(4.5):4.5 is rounded up to 5.0.Adding the Results:6.0 + 5.0 = 11.0

Question 4

Question 1(ix)What is the method to check whether a character is a letter or digit?isDigit(char)isLetterOrDigit()isLetterOrDigit(char)isLETTERorDIGIT(char)

Accepted Answer

isLetterOrDigit(char)Reason — In Java, the method Character.isLetterOrDigit(char ch) is used to check whether a given character ch is either a letter (A-Z or a-z) or a digit (0-9).Analysing Other Options:isDigit(char) – This method only checks if the character is a digit, not a letter.isLetterOrDigit() – Incorrect because this method requires a character parameter.isLETTERorDIGIT(char) – Java methods are case-sensitive, and method names follow camelCase. This method name does not exist.

Question 5

Question 1(x)The extension of a Java source code file is:exeobjjvmjava

Accepted Answer

javaReason — In Java, source code files are saved with the .java extension. These files contain the Java program's source code, written in human-readable text format.

Question 6

Question 1(xi)The number of bytes occupied by a character array of four rows and three columns are:12249648

Accepted Answer

24Reason — In Java, a character (char) takes 2 bytes because Java uses Unicode encoding.Given:Character Array: 4 rows and 3 columnsTotal Elements = 4 × 3 = 12 charactersMemory Calculation:Each character = 2 bytesTotal Memory = 12 × 2 = 24 bytes

Question 7

Question 1(xii)Which of the following data type cannot be used with switch case construct?intcharStringdouble

Accepted Answer

doubleReason — The switch statement in Java supports specific data types for the case labels. However, double and float data types cannot be used.Data Types supported in switch statement are:intcharString

Question 8

Question 1(xiii)Which of the following are entry controlled loops?(a) for(b) while(c) do..while(d) switchonly aa and ba and cc and d

Accepted Answer

a and bReason — An entry-controlled loop checks the loop condition before executing the loop's body. If the condition is false at the start, the loop's body will not execute even once.for and while loops check the condition before running the loop's body. If the condition is false, the loop won't run. Therefore, they are entry controlled loops.The body of the do-while loop executes at least once before checking the condition. Hence, it is an exit controlled loop.

Question 9

Question 1(xiv)Method which reverses a given number is:Impure methodPure methodConstructorDestructor

Accepted Answer

Pure methodReason — A pure method in Java is a method that:Returns a value based only on its input arguments.Does not modify any external variables or system state.Does not change any class fields or input values.In the context of reversing a number, a pure method accepts the number as input and returns its reversed form without altering any external state.

Question 10

Question 1(xv)If the name of the class is "Yellow", what can be the possible name for its constructors?yellowYELLOWYellYellow

Accepted Answer

YellowReason — In Java, a constructor must have the same name as the class. It initializes an object when it is created. Since the class name is Yellow, the constructor's name must be exactly Yellow, matching the class name including capitalization.

Question 11

Question 1(xvi)Invoking a method by passing the objects of a class is termed as:Call by referenceCall by valueCall by methodCall by constructor

Accepted Answer

Call by referenceReason — When an object is passed to a method:The method receives a reference (memory address) to the original object.Any changes made inside the method affect the original object.

Question 12

Question 1(xvii)The correct statement to create an object named mango of class fruit:Fruit Mango= new fruit();fruit mango = new fruit();Mango fruit=new Mango();fruit mango= new mango();

Accepted Answer

fruit mango = new fruit();Reason — In Java, creating an object follows the syntax:ClassName objectName = new ClassName();Where:ClassName: The name of the class.objectName: The name of the object.new: Allocates memory for the object.ClassName(): Calls the class's constructor.Thus, fruit mango = new fruit(); correctly creates mango named object of fruit class.

Question 13

Question 1(xviii)Assertion (A): Static method can access static and instance variables.Reason (R): Static variable can be accessed only by static method.Assertion and Reason both are correct.Assertion is true and Reason is false.Assertion is false and Reason is true.Assertion and Reason both are false.

Accepted Answer

Assertion and Reason both are false.Reason — A static method can only access static variables and static methods directly because it belongs to the class, not any specific object. Hence, Assertion is false.Both instance and static methods can access static variables. Hence, Reason is false.

Question 14

Question 1(xix)What is the output of the Java code given below?String color[] = {"Blue", "Red", "Violet"};
System.out.println(color[2].length());6532

Accepted Answer

6Reason — The given Java code declares and initializes a String array color with three elements. The array elements are:color[0] = "Blue"color[1] = "Red"color[2] = "Violet"The method length() returns the number of characters in the string "Violet".

Question 15

Question 1(xx)Which of the following mathematical methods returns only an integer?Math.ceil(n)Math.sqrt(n)Math.floor(n)Math.round(n)

Accepted Answer

Math.round(n)Reason — In Java, Math.round(n) is the only method in the list that returns an integer when called with a floating-point number (float or double).

Question 16

Question 2(i)Write Java expression for:∣𝑎+𝑏∣a2+b2\dfrac{|𝑎 + 𝑏|}{\sqrt{a^2 + b^2}}a2+b2​∣a+b∣​

Accepted Answer

The Java expression for the given mathematical expression can be written as:double result = Math.abs(a + b) / Math.sqrt(Math.pow(a, 2) + Math.pow(b, 2));

Question 17

Question 2(ii)Evaluate the expression when x is 4:x += x++ * ++x % 2;

Accepted Answer

The given expression is evaluated as follows:x += x++ * ++x % 2x = x + (x++ * ++x % 2) (x = 4)x = 4 + (4 * ++x % 2) (x = 5)x = 4 + (4 * 6 % 2) (x = 6)x = 4 + (24 % 2) (x = 6)x = 4 + 0 (x = 6)x = 4

Question 18

Question 2(iii)Rewrite the following do while program segment using for:x = 10; y = 20;
do
{
    x++;
    y++;
} while (x<=20);
System.out.println(x * y );

Accepted Answer

Below is the for loop version of the provided do-while segment:public class Main {
    public static void main(String[] args) {
        int x = 10, y = 20;

for (; x <= 20; x++, y++) {
            // Body is empty because the increments are in the for loop header
        }

System.out.println(x * y);
    }
}

Question 19

Question 2(iv)Give the output of the following program segment. How many times is the loop executed?for(x=10; x>20;x++)

System.out.println(x);

System.out.println(x*2);

Accepted Answer

Output20
The loop executes 0 times because the loop condition x>20 is false as value of x is 10.

Question 20

Question 2(v)String s1 = "45.50"; String s2 = "54.50";
double d1=Double.parseDouble(s1);
double d2=Double.parseDouble(s2);
int x= (int)(d1+d2);What is value of x?

Accepted Answer

100Reason — The code converts the strings "45.50" and "54.50" into doubles using Double.parseDouble(), resulting in d1 = 45.5 and d2 = 54.5. Their sum is 100.0.Casting 100.0 to an integer using (int) removes the decimal part, leaving x = 100.

Solved 2024 Question Paper ICSE Class 10 Computer Applications

Section A

Section B