1. Data representation
A section of Computer Science, 0478
Listing 10 of 123 questions
A sports stadium has an electronic counter that counts each person that enters the stadium. The count is stored as binary in a 16-bit register. A denary value of the count is displayed on a screen at the entrance. The screen currently displays: 0 0 7 1 Give the binary value that is stored in the register to display the count shown. Binary value: Working space More people enter the sports stadium and the screen now displays: 0 2 5 7 Give the binary value that is stored in the register to display the count shown. Binary value: Working space After everyone has entered the stadium, the register stores the binary value: Show what the screen will display when this binary value is stored. Display: Working space Sensors are used at the entrance to count the number of people entering the stadium. Identify two sensors that could be used to count the number of people entering the stadium. Sensor 1 Sensor 2 Tick (3) one box to show if a sensor is an example of an input device, storage device or output device. Device Tick (✔) input storage output
0478_w21_qp_13
THEORY
2021
Paper 1, Variant 3
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A car park has a payment machine that allows a customer to pay for their parking. The cost of parking is displayed as a denary number on a screen on the payment machine. The cost of parking is stored in two 8-bit binary registers. For the parking cost of $10.50: • register 1 stores the denary value 10 as binary • register 2 stores the denary value 50 as binary. Give the parking cost that would be displayed on the payment machine when the registers store: • register 1: 00010001 • register 2: 01000110 Parking cost displayed $ Working space The parking cost of $14.98 is displayed on the payment machine. Give the 8-bit binary numbers that are stored in the registers to display the parking cost. Register 1 Register 2 Working space The payment machine gives the customer a ticket when they have paid their parking cost. Each ticket has a 4-digit hexadecimal ticket number that is stored as binary. The binary number 1010000000111101 is stored for a customer’s ticket number. Give the hexadecimal ticket number that would be displayed on this customer’s ticket. Hexadecimal ticket number Working space Explain why data input into the payment machine needs to be converted to binary. When a customer is leaving the car park they arrive at a barrier. The customer needs to insert their ticket into a system at the barrier. This system reads the ticket number then checks whether the parking cost has been paid for the car. The barrier is raised if it has been paid. The system uses a microprocessor. Describe the role of the microprocessor in the system and how it checks whether the parking cost has been paid.
0478_w23_qp_11
THEORY
2023
Paper 1, Variant 1
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Humans use a denary number system and computers use a binary number system. Explain what is meant by a binary number system. Convert the denary numbers 14, 59 and 234 to binary. Working space Convert the denary numbers 9, 26 and 65 to hexadecimal. Working space Convert the positive denary number 123 to 8-bit binary using two’s complement. Show all your working. Add the binary values 00110011 and 01111000 using binary addition. Give your answer in binary. Show all your working.
0478_w23_qp_13
THEORY
2023
Paper 1, Variant 3
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Data can be measured using different units of storage. Tick (✓) one box to show which of the following is the largest unit of data storage. A tebibyte (TiB) B pebibyte (PiB) C mebibyte (MiB) D gibibyte (GiB) A computer has primary storage. Give one example of primary storage. Explain the purpose of your chosen example. Example Explanation All data is converted to binary to be processed by a computer. Calculate the binary number for the denary number 175. Show all your working. Give the binary number for the given hexadecimal numbers. 2D Working space Binary integers can be added together. Add the two binary integers using binary addition. Show all your working. Give your answer in binary. 1 1 1 0 0 0 1 1 + 1 1 0 0 1 1 0 0 Calculate the denary number for the two’s complement binary integer 10001110. Show all your working.
0478_w24_qp_13
THEORY
2024
Paper 1, Variant 3
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A long distance running race uses an electronic counter that counts each competitor who finishes the race. The count is stored as binary in a 12-bit register. A denary value of the count is displayed on a screen above the finish line. The screen currently displays: State the binary value that is currently stored to display the count shown. More competitors cross the finish line and the screen now displays: State the binary value that is currently stored to display the count shown. At the end of the race the binary value stored is: Give the denary value that would be displayed on the screen at the end of the race. Show your working. Screen display: Sensors are used at the finish line to identify the number of competitors who finish the race. Identify two different sensors that could be used to identify the number of competitors. Sensor 1 Sensor 2 The sensors are used with a microprocessor to count how many competitors finish the race. Explain how the sensor and the microprocessor are used.
0478_m19_qp_12
THEORY
2019
Paper 1, Variant 2
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A hockey club records the number of people that watch each match. An 8-bit binary register is used to store this value. 46 people watch the first match and 171 people watch the second match. Show how the registers would store these denary values as 8-bit binary. Denary value 8-bit binary Working space Give the largest denary value that can be stored in the 8-bit binary register. The hockey club wants to increase the number of people that can watch each match to 2000. The 8-bit binary register may no longer be able to store the value. Give the smallest number of bits that can be used to store the denary value 2000. Working space Electronic data about the final score for the match is transmitted to a central computer 30 kilometres away, using serial transmission. Explain why serial transmission is more appropriate than parallel transmission in this scenario. The data transmission is also half-duplex. Describe half-duplex data transmission. The data transmission uses checksums. Describe how checksums are used to detect errors in data transmission.
0478_m21_qp_12
THEORY
2021
Paper 1, Variant 2
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Hexadecimal can be used to represent binary numbers. Convert the denary number 236 into hexadecimal. Working space Give one benefit of using hexadecimal instead of binary to represent data. Two’s complement can be used to represent positive and negative binary integers. Convert the two’s complement integer 10110111 into denary. Show all your working. Convert the denary number 45 into an 8-bit two’s complement integer. Working space Logical shifts are performed on binary integers. State the mathematical effect of a right shift of four places on a positive binary integer.
0478_m24_qp_12
THEORY
2024
Paper 1, Variant 2
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Questions Discovered
123