0478_m22_qp_12 - revisedeck

0478_m22_qp_12

A paper of Computer Science, 0478

Questions:

7

Year:

2022

Paper:

1

Variant:

2

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1

A computer stores data in binary form. Binary numbers can be represented as hexadecimal and denary numbers. Convert the 8-bit binary number 01010101 to denary. Working space Convert the binary number 11000000 to hexadecimal. Working space Convert the hexadecimal number 1A to denary. Working space Binary numbers can be stored as bytes. State how many bits are in two bytes.

1. Data representation → 1.1. Number systems

Open

2

Nadia creates a digital image for a school project. Give one example of an image format. Describe how a digital image file is stored by a computer. Nadia compresses the digital image file before emailing it to a friend. State what is meant by data compression. Explain why Nadia compresses the digital image file before emailing it. Nadia’s email service uses parity bits as a method of error detection during the transmission of data. Describe how the parity bits are used to detect errors. Identify and describe one other method of error detection used during the transmission of data. Method Description

1. Data representation → 1.3. Data storage and compression

2. Data transmission → 2.1. Types and methods of data transmission

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3

Tick (3) to show which logic gates will give an output of 1 for the given inputs A and B. Inputs AND OR NAND NOR XOR A = 1 B = 1 A = 0 B = 0 A = 1 B = 0 Draw the logic circuit for the given logic statement: X = (A XOR B) AND (B OR NOT C) Do not attempt to simplify the logic statement. All logic gates must have a maximum of two inputs. X B A C

10. Boolean logic → 10. Boolean logic

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4

Pradeep uses his personal computer to complete work at home. Pradeep uses a mouse and a keyboard to control the computer. Complete the descriptions of the principles of operation of a mouse and a keyboard using the most appropriate terms from the list. Not all terms in the list need to be used. • absorbs • ball • biometric • circuit • colour • digital • direction • Light-Emitting Diode (LED) • Liquid Crystal Display (LCD) • reflects • speed • switch • transparency An optical mouse shines a red light from a underneath the mouse. The light back from a surface through a lens in the mouse and is converted to a value. This value is transmitted to the computer. The computer then determines the and of the movement. When the user presses a key on a keyboard, the key pushes the on the circuit board. This completes a . Signals are sent to the computer. The computer uses the data to calculate which key was pressed. Identify two other input devices Pradeep could use with his personal computer. Input device 1 Input device 2 Pradeep uses a projector attached to the ceiling at his home to watch high-definition (HD) films. The projector has broken. He wants to buy a replacement. He needs to choose between an LCD projector and a Digital Light Projector (DLP). Explain why an LCD projector would be more appropriate for Pradeep. Pradeep stores his collection of films and his work files on his personal computer. Pradeep wants to save a copy of all his films and files onto a single storage device. Identify and justify an appropriate storage device to store the copies. Storage device Justification

3. Hardware → 3.2. Input and output devices

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5

A holiday company has a website where customers can create accounts and can book and pay for holidays. The website is written in Hypertext Markup Language (HTML). Give two examples of HTML structure and two examples of HTML presentation. Structure 1 Structure 2 Presentation 1 Presentation 2 The website is stored on a web server. Customers use their own computers to access the website. Uniform Resource Locator (URL), Internet Protocol (IP) and Media Access Control (MAC) are three types of address used by computers when accessing the Internet. Give two features of each type of address in the table. Type of address Features URL IP MAC The company is concerned about threats to its web server. Complete the table by identifying: • two potential threats to its web server • the impact each threat could have on the company • software the company can use to help to limit each threat. Each impact must be different. Threat Impact on company Software

5. The internet and its uses → 5.3. Cyber security

5. The internet and its uses → 5.1. The internet and the world wide web

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6

A business uses a closed-circuit television (CCTsystem that starts recording when motion is detected. It stops recording after two minutes if no further motion is detected. The system uses a motion sensor and a microprocessor. Describe how the motion sensor and microprocessor work together to control the CCTV system.

3. Hardware → 3.1. Computer architecture

6. Automated and emerging technologies → 6.1. Automated systems

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7

Ishani is a software developer who is creating a new computer game. Ishani uses an interpreter and a compiler at different stages of the game creation. Explain when it is most appropriate for Ishani to use an interpreter. Explain when it is most appropriate for Ishani to use a compiler. Ishani has to decide between releasing her game as freeware or free software. Describe freeware and free software. Freeware Free software

4. Software → 4.2. Types of programming language, translators and integrated development environments (IDEs)

4. Software → 4.1. Types of software and interrupts

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