AQA GCSE Computer Science Paper 2: Computing concepts June 2022 question paper 8525/2

Convert the binary number 11010100 into decimal.

Convert the binary number 10111001 into hexadecimal.

You should show your working.

State the largest decimal number that can be represented using 6 bits.

Apply a binary shift three places to the right on the bit pattern 10101000

Give the result using 8 bits.

The arithmetic effect of applying a left binary shift of two to a binary number is to multiply that number by four.

State the arithmetic effect of applying a left binary shift of four to a binary number.

State the arithmetic effect of applying a left binary shift of three followed by a right binary shift of five to a binary number.

Complete the truth table for the XOR logic gate.

Another circuit in the game will output True if any two sensors are activated or if all three sensors are activated. This has been represented as the Boolean expression:

The expression contains an error.

Shade one lozenge that shows the expression with the error corrected.

A green light (G) in the game switches on if all of the following conditions are true:

• sensor D is off

• sensor L is off

• sensor W is on.

Write a Boolean expression for this logic circuit.

You must use Boolean expression operators in your answer.

Describe what is meant by the terms system software and application software.

System software

Application software

State four functions of an operating system.

An autonomous vehicle is controlled by a computer system, senses its environment and requires no input from a human driver.

Discuss the legal and ethical impacts that need to be considered when replacing manual, human-driven vehicles with autonomous vehicles.

Programming languages can be classified as low-level or high-level.

Shade two lozenges to show the statements that are true about code written using a low-level language instead of a high-level language.

Assemblers and interpreters are two types of program translator.

State the purpose of an assembler.

Explain how an interpreter works.

State two reasons why computers have more RAM than cache memory.

Data is increasingly being stored ‘in the cloud’.

State two advantages of using cloud storage instead of local storage.

Many new computers use solid-state storage for secondary storage rather than magnetic storage.

Explain why solid-state storage is not fitted to every new computer.

How many bits are there in two kilobytes?

Show your working.

bits

The ASCII value for the character x is the decimal number 120

Complete Table 1 with the missing ASCII and Unicode values.

Figure 1 shows a 10 x 8 bitmap image that uses three colours.

Calculate the minimum file size that would be required to store the bitmap image in Figure 1.

Give your answer in bytes.

Show your working.

bytes

Analogue sound must be converted to a digital form for storage and processing in a computer.

Define the term sample resolution.

State one disadvantage of a high sample resolution.

A 50-second sound has been recorded at a sample rate of 40 000 Hz. Two bytes have been used to store each sample of the sound.

Calculate the file size of the sound file in megabytes.

Show your working.

Computer networks can be installed using wired or wireless technology.

State one wireless method used to connect devices on a Personal Area Network (PAN).

Describe two differences between a Local Area Network (LAN) and a Wide Area Network (WAN).

Give three advantages of using a wireless network instead of a wired network.

Shade one lozenge to indicate the application layer protocol used for sending emails from a client device to a mail server.

Explain the purpose of the HTTPS protocol.

State two issues with only using usernames and passwords in an authentication system.

Describe one security measure that could be used, in addition to a password, to make sure that a user is who they are claiming to be.

State two reasons why automatic software updates provide better security than manual software updates.

Explain what penetration testing is.

Describe the aim of a white-box penetration test.

State two reasons why data are compressed.

Figure 2 shows a string.

Figure 2

MISSISSIPPI

One method for compressing data is run length encoding (RLE).

When using RLE, the data in Figure 2 become:

1M 1I 2S 1I 2S 1I 2P 1I

Explain why RLE is not a suitable method for compressing the data in Figure 2.

Another method for compressing data is Huffman coding. In Huffman coding, the codes for the characters can be created based on their position in a tree.

Figure 3 shows a Huffman code for each different character in the string in Figure 2.

Complete the Huffman tree below to show the position of the characters I, S and P using the codes from Figure 3.

A relational database has been developed for a youth club to store information about their members and the awards they are given.

The database contains two tables: Member and Award

Figure 4 shows some data from the tables.

Figure 4

Define the term relational database.

State one benefit of using relational databases.

State the name of the field from the Member table that is the most suitable to use as the primary key.

State the name of the field from the Award table that is a foreign key.

Figure 4 has been included again below.

Figure 4

The youth club needs to produce a report listing the members who have been given the Leader award. The report must include both names of each member and the date the award was presented.

Write an SQL query that could be used to find this information. The results must be in order of the date the awards were presented, starting with the earliest.