Learn Extracted exam questions A-Level Computer Science 9618 Computer Science June 2025 Question Paper 11
9618 Computer Science June 2025 Question Paper 11
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Write the logic expressions for the following logic circuit.
X = \hrulefill Y = \hrulefill
Complete the truth table for the following logic circuit.
\begin{tabular}{|c|c|c|c|} \hline \textbf{A} & \textbf{B} & \textbf{C} & \textbf{X} \ \hline 0 & 0 & 0 & \ \hline 0 & 0 & 1 & \ \hline 0 & 1 & 0 & \ \hline 0 & 1 & 1 & \ \hline 1 & 0 & 0 & \ \hline 1 & 0 & 1 & \ \hline 1 & 1 & 0 & \ \hline 1 & 1 & 1 & \ \hline \end{tabular}
Programmers in a software development company take part in live video conferences to discuss their work.
The live video conferences take place using real-time bit streaming. The video is compressed before it is transmitted.
Explain how data is transferred using real-time bit streaming.
Explain the reasons why a video is compressed before it is transmitted using real-time bit streaming.
Identify whether the lossy or lossless compression method is more appropriate for real-time bit streaming. Justify your answer.
Compression method \hrulefill
The video conference is accessed over the internet.
Complete the table by stating how modems \textbf{and} dedicated lines are used when data is transmitted over the internet.
\begin{tabular}{|l|p{10cm}|} \hline \textbf{Hardware} & \textbf{Use} \ \hline modems & \ & \ \hline dedicated lines & \ & \ \hline \end{tabular}
A computer stores images and text files.
One of the images is a bitmapped image.
Complete the table by writing the answer for each statement.
\begin{tabular}{|p{5cm}|p{5cm}|} \hline \textbf{Statement} & \textbf{Answer} \ \hline the term for the smallest element that makes up an image & \ \hline the largest number of different colours that can be represented with a bit depth of 8 bits & \ \hline the term for the dots per inch (dpi) when an image is displayed & \ \hline \end{tabular}
The text in the files is stored using the Unicode character set.
Give \textbf{two} advantages of using the Unicode character set instead of using the ASCII character set.
- \hrulefill
- \hrulefill
The Unicode character '❮' has the binary value: 0010 0111 0110 1110
Convert the binary value for the character '❮' into denary.
The Unicode character '⅀' has the hexadecimal value 2140
Convert the hexadecimal code for the character '⅀' into denary.
A shop installs a new system that allows users to purchase items without going through a manual checkout.
The new system: \begin{itemize} \item identifies customers when they enter the shop and matches them to their account \item prevents a customer from walking through the automatic barriers if they do not have an account \item automatically detects the items that a customer has taken from a shelf and charges these to the customer's account. \end{itemize}
The new system uses digital cameras and Artificial Intelligence (AI) to identify the customers.
Explain how the new system uses AI to identify each customer.
The new system uses sensors to identify the items taken from a shelf.
Identify \textbf{one} type of sensor that can be used in this new system.
State how the sensor can be used to identify the items taken from a shelf.
Sensor \hrulefill
Use \hrulefill
A company builds and sells furniture to customers. The company stores data about customers, their payment cards and their furniture orders in a database.
The database, \texttt{FURNITURE}, has the following tables:
\texttt{CUSTOMER}(\underline{CustomerID}, Name, Phone)
\texttt{CUSTOMER_CARD_DATA}(\underline{CardID}, CustomerID, CardType, CardNumber, EndDate)
\texttt{ORDER}(\underline{OrderID}, CustomerID, TotalCost, Paid, OrderDate, Complete)
\texttt{ORDER_ITEM}(\underline{OrderItemID}, OrderID, Type, Height, Width, Depth, Details)
The primary keys are underlined in each table.
The attribute \texttt{Complete} in the table \texttt{ORDER} stores the Boolean value \texttt{TRUE} if the order has been built and \texttt{FALSE} if the order has not been built.
Complete the entity-relationship (E-R) diagram for the database.
Identify one attribute in the table \texttt{CUSTOMER_CARD_DATA} that could be a candidate key.
Identify \textbf{two} tables in the database that contain one or more foreign keys. Give \textbf{one} attribute that is a foreign key in each table.
\begin{tabular}{|c|c|c|} \hline & \textbf{Table} & \textbf{Foreign key} \ \hline 1 & & \ \hline 2 & & \ \hline \end{tabular}
Explain the reasons why the data in the table \texttt{ORDER_ITEM} cannot be stored in the table \texttt{ORDER}
Write an Structured Query Language (SQL) script to output the customer ID, the customer's name and the total cost of the customer's orders that have not been paid.
The output of the total cost must have an appropriate title.
A programmer is buying a new computer.
The programmer is considering the following two computers:
\begin{tabular}{|p{3cm}|p{8cm}|} \hline Computer 1 & Quad-core 2.2 GHz processor \newline 16-bit architecture \newline 1 GB Random Access Memory (RAM) \newline 500 GB magnetic hard disk \ \hline Computer 2 & Dual-core 3.8 GHz processor \newline 32-bit architecture \newline 2 GB RAM \newline 500 GB solid state drive (SSD) \ \hline \end{tabular}
Computer 1 has a magnetic hard disk.
Complete the description of the principal operation of a magnetic hard disk by writing the missing words.
The magnetic hard disk has one or more \underline{\hspace{1.5em}} that can be magnetised. These are mounted on a \underline{\hspace{1.5em}} and rotate at high speed.
A \underline{\hspace{1.5em}} is moved across the surface on an arm.
When data is read, the changes in the \underline{\hspace{1.5em}} produce a change in the electric current.
The two computers have different amounts of RAM.
Explain how different amounts of RAM affect the performance of a computer.
The two computers have different bus widths.
Explain how different bus widths affect the performance of a computer.
Both computers have an Operating System (OS).
Describe the purpose of an OS in a computer.
A banker stores personal data on their work computer.
The banker needs to transfer confidential data across the internet.
Identify and describe \textbf{one} method of restricting the risks posed by an unauthorised person intercepting the data whilst it is being transferred across the internet.
Method \hrulefill
Description
The banker receives confidential data across the internet. The data includes a digital signature.
Explain how a digital signature can make sure the data has \textbf{not} been changed during transmission.
The data that is transferred can also be verified using a checksum.
Explain how data can be verified using a checksum.
The following table shows part of the instruction set for a processor. The processor has two registers: the Accumulator (ACC) and an Index Register (IX).
\begin{tabular}{|l|l|l|} \hline \multicolumn{2}{|c|}{\textbf{Instruction}} & \multicolumn{1}{c|}{\textbf{Explanation}} \ \cline{1-2} \textbf{Opcode} & \textbf{Operand} & \ \hline LDM & #n & Immediate addressing. Load the number n to ACC \ \hline LDD & \texttt{
} & Direct addressing. Load the contents of the location at the given address to ACC \ \hline LDI & \texttt{} & Indirect addressing. The address to be used is at the given address. Load the contents of this second address to ACC \ \hline INC & \texttt{\begin{itemize} \item ACC denotes Accumulator \item \texttt{
} can be an absolute or a symbolic address \item # denotes a denary number, e.g. #123 \item B denotes a binary number, e.g. B01001010 \item & denotes a hexadecimal number, e.g. &4A \end{itemize}The table shows part of the instruction set for a processor. The processor has one register: the Accumulator (ACC).
\begin{tabular}{|l|l|l|} \hline \multicolumn{2}{|c|}{\textbf{Instruction}} & \multicolumn{1}{c|}{\textbf{Explanation}} \ \cline{1-2} \textbf{Opcode} & \textbf{Operand} & \ \hline \texttt{AND} & \texttt{#n/Bn/&n} & Bitwise AND operation of the contents of ACC with the operand \ \hline \texttt{AND} & \texttt{
} & Bitwise AND operation of the contents of ACC with the contents of \texttt{} \ \hline \texttt{XOR} & \texttt{#n/Bn/&n} & Bitwise XOR operation of the contents of ACC with the operand \ \hline \texttt{XOR} & \texttt{} & Bitwise XOR operation of the contents of ACC with the contents of \texttt{} \ \hline \texttt{OR} & \texttt{#n/Bn/&n} & Bitwise OR operation of the contents of ACC with the operand \ \hline \texttt{OR} & \texttt{} & Bitwise OR operation of the contents of ACC with the contents of \texttt{} \ \hline \texttt{LSL} & \texttt{#n} & Bits in ACC are shifted logically n places to the left. Zeros are introduced on the right-hand end \ \hline \texttt{LSR} & \texttt{#n} & Bits in ACC are shifted logically n places to the right. Zeros are introduced on the left-hand end \ \hline \multicolumn{3}{|l|}{\texttt{} can be an absolute or symbolic address} \ \multicolumn{3}{|l|}{# denotes a denary number, e.g. #123} \ \multicolumn{3}{|l|}{B denotes a binary number, e.g. B01001010} \ \multicolumn{3}{|l|}{& denotes a hexadecimal number, e.g. &4A} \ \hline \end{tabular}Write the bit manipulation instruction that can be used to set the least significant bit to 1 in an 8-bit register. All other bits must remain unchanged.
The instruction needs to work on a register that contains any 8-bit binary number.
The ACC currently contains the following binary value.
\begin{tabular}{|c|c|c|c|c|c|c|c|} \hline 0 & 1 & 0 & 1 & 0 & 1 & 0 & 1 \ \hline \end{tabular}
Write the result after the instruction \texttt{XOR &FE} is run.
\framebox{$\square\,\square\,\square\,\square\,\square\,\square\,\square\,\square$}
The ACC currently contains the following binary value.
\begin{tabular}{|c|c|c|c|c|c|c|c|} \hline 0 & 1 & 1 & 0 & 1 & 0 & 1 & 1 \ \hline \end{tabular}
Write the result after the instruction \texttt{LSR #5} is run.
\framebox{$\square\,\square\,\square\,\square\,\square\,\square\,\square\,\square$}