IGCSE Computer Science Mock

For Mocks

What is binary?

A number system using only 0 and 1

Why do computers use binary?

Because digital systems only recognize two voltage states

What is a bit?

The smallest unit of data in computing

What is a nibble?

A group of four bits.

What is a byte?

A group of 8 bits.

What is a kilobyte?

A unit of digital data equal to 1

How do you convert binary to denary?

By multiplying each bit by its place value and adding the results.

What is hexadecimal?

A base-16 number system using digits 0-9 and letters A-F.

Why is hexadecimal used?

It simplifies binary representation

How do you convert hexadecimal to binary?

Convert each hex digit to its 4-bit binary equivalent.

What is ASCII?

A character encoding system using 7 or 8 bits to represent characters.

How many characters can standard ASCII represent?

128 characters using 7 bits.

What is extended ASCII?

An 8-bit version of ASCII that can represent 256 characters.

What is Unicode?

A character encoding standard that can represent characters from many world languages.

What is an image file?

A file made of pixels

What is resolution?

The number of pixels in an image

What is color depth?

The number of bits used to represent the color of a single pixel.

How is sound represented in binary?

Through sampling the amplitude of sound waves at regular intervals.

What is sample rate?

The number of samples taken per second when recording sound.

What is sample resolution?

The number of bits used per sample in a sound recording.

What is compression?

Reducing the size of a file to save storage or transmission time.

What is lossless compression?

A compression technique where no data is lost

What is lossy compression?

A method that removes some data permanently to reduce file size.

What is an algorithm?

A step-by-step method for solving a problem.

What is pseudocode?

A way to plan code using structured English.

What is a flowchart?

A diagram that represents an algorithm using symbols.

What is selection in algorithms?

Using conditions to decide between different actions

What is iteration?

The repetition of steps using loops.

What is a variable?

A named storage location in a program that can change during execution.

What is a constant?

A fixed value that does not change during program execution.

What is a data type?

The kind of data a variable holds

What is debugging?

Finding and fixing errors in a program.

What is a syntax error?

A mistake in the code that breaks the programming language rules.

What is a logic error?

An error that causes the program to run incorrectly but not crash.

What is a runtime error?

An error that occurs while the program is running

What is a subroutine?

A set of instructions in a program that performs a specific task.

What is a function?

A subroutine that returns a value.

What is a procedure?

A subroutine that does not return a value.

What is a parameter?

A variable passed into a subroutine.

What is SQL?

Structured Query Language

What is a database?

An organized collection of data stored electronically.

What is a table in a database?

A structure in a database made up of rows and columns.

What is a field?

A single piece of data in a database record.

What is a record?

A complete set of fields in a table.

What is a primary key?

A unique identifier for each record in a database table.

What is a query?

A request to retrieve or manipulate data in a database.

What is Boolean logic?

A form of logic that uses TRUE and FALSE values.

What does AND mean in Boolean logic?

A condition is true only if all conditions are true.

What does OR mean in Boolean logic?

A condition is true if at least one condition is true.

What does NOT mean in Boolean logic?

It inverts a Boolean value: TRUE becomes FALSE and vice versa.

What is a truth table?

A table that shows all possible combinations of inputs and outputs in Boolean logic.

How is Boolean logic used in programming?

It controls the flow of a program using conditions in decision-making.

What is an overflow error?

An error that occurs when a calculation exceeds the maximum limit a data type can hold.

What is a hexadecimal digit?

A single character in base-16

How are characters stored in binary?

Each character is assigned a binary value using encoding schemes like ASCII or Unicode.

Why is Unicode better than ASCII?

Unicode can represent a wider range of global characters and symbols.

What is metadata in images?

Data that describes the image

How does increasing resolution affect file size?

Higher resolution means more pixels

How does increasing sample rate affect sound quality?

More samples per second gives more accurate sound representation.

Why do we use compression?

To reduce file size for faster transmission and to save storage space.

What is RLE compression?

Run-Length Encoding compresses data by storing repeated values as a single value and count.

How do you convert denary to binary?

Divide the number by 2 repeatedly and read the remainders in reverse.

What is a flowchart terminator symbol?

An oval shape used to show start or end of a process.

What is a process symbol in a flowchart?

A rectangle used to show an action or instruction.

What is a decision symbol in a flowchart?

A diamond shape used to show a yes/no or true/false choice.

What is a loop?

A programming structure that repeats a block of code multiple times.

What is a FOR loop?

A loop that repeats a fixed number of times.

What is a WHILE loop?

A loop that repeats while a condition is true.

What is a REPEAT...UNTIL loop?

A loop that repeats until a condition becomes true.

What is input?

Data received by a computer from the user or another system.

What is output?

Data sent from the computer to the user or another system.

What is an IDE?

An Integrated Development Environment where you can write

What is a trace table?

A table used to manually track variables and outputs during code execution.

What is a test plan?

A list of tests used to check whether a program works correctly.

What is a comment in programming?

A non-executing line that explains code to humans.

What is a string?

A sequence of characters

What is an integer?

A whole number

What is a float/real?

A number that includes a decimal point.

What is a boolean?

A data type with only two values: TRUE or FALSE.

What is a syntax check?

A tool in the IDE that checks for incorrect language structure.

What is a logic gate?

An electronic component that performs a logical operation using binary inputs.

What is an AND gate?

A logic gate that outputs TRUE only if all inputs are TRUE.

What is an OR gate?

A logic gate that outputs TRUE if at least one input is TRUE.

What is a NOT gate?

A gate that outputs the opposite of the input.

What is a NAND gate?

A gate that outputs the opposite of an AND gate.

What is a NOR gate?

A gate that outputs the opposite of an OR gate.

What is an XOR gate?

A gate that outputs TRUE if only one input is TRUE.

How do you simplify Boolean expressions?

Using Boolean algebra rules like De Morgan’s laws.

What is a flat file database?

A database that stores all data in one table.

What is a relational database?

A database that uses multiple linked tables.

What is a foreign key?

A field in one table that links to a primary key in another.

Why use relational databases?

To reduce data redundancy and improve data integrity.

What is a form in a database?

A user-friendly interface to input or view records.

What is a report in a database?

A formatted way of presenting data from queries.

What is data validation?

A process to ensure data entered is reasonable and sensible.

What is data verification?

A process to ensure data entered is correct

What is the purpose of a DBMS?

Database Management Systems allow users to create

What is an array?

A collection of elements stored under one variable name.

What is a one-dimensional array?

An array with one row of elements.

What is a two-dimensional array?

An array structured in rows and columns.