1.1. Number systems
A subsection of Computer Science, 0478, through 1. Data representation
Listing 10 of 71 questions
Jane answers an examination question about computers and data correctly. Six different words or numbers have been removed from her answer. Complete the sentences in Jane’s answer, using the list given. Not all items in the list need to be used. • • • • analogue • binary • denary • digital • hexadecimal As humans, we process …………………………………… data, but a computer cannot process this type of data. For a computer to be able to process data it needs to be converted to …………………………………… data. As humans, we mostly use a …………………………………… number system; this is a base …………………………………… number system. Computers use a …………………………………… number system; this is a base …………………………………… number system.
0478_s18_qp_11
THEORY
2018
Paper 1, Variant 1
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An aeroplane has a small display screen above each seat, to display the seat number. The seat number is a hexadecimal value. A 12-bit binary register is used to store the data to display each seat number. Three seat numbers, 05A, 18C and 29F, are allocated to passengers. Give the 12-bit binary value that would be stored for each hexadecimal seat number. 05A 18C 29F Working space The display screen used above each seat is a Light-Emitting Diode (LED) display screen. Give two reasons why an LED display screen has been used. Reason 1 Reason 2 Two of the registers store the values 010000001101 and 000001111110 Give the hexadecimal seat number that would be displayed on the screen for each of these binary values. Working space
0478_s22_qp_13
THEORY
2022
Paper 1, Variant 3
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Computers store data as binary. The binary number 10101110 is stored. Convert the binary number to denary. Working space Convert the binary number to hexadecimal. Working space A logical left shift of three places is performed on the binary number. Give the 8-bit binary number that would be stored after this logical left shift. Tick (3) one box to show which statement is true about the impact the logical left binary shift would have on the binary number. A The least significant bits are lost. B The most significant bits are lost. C The number has been divided by six. D The number stays the same. Add the two 8-bit binary numbers 11101110 and 00110001 using binary addition. Give your answer in binary. Show all your working. The denary number 301 needs to be stored. Calculate the least number of bits that can be used to store the denary number 301. Working space The hexadecimal number A4D needs to be stored. Calculate the least number of bits that can be used to store the hexadecimal number A4D. Working space
0478_s23_qp_13
THEORY
2023
Paper 1, Variant 3
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Binary is a base 2 number system. Give the name of the number system that is base 16. Three denary numbers are entered into a computer. The computer converts the numbers and stores them as binary. Give the binary number that would be stored for each of the denary numbers. Working space Explain why the data is converted to binary by the computer. The two binary integers 00110000 and 01100110 are added together. Add the binary integers using binary addition and show your answer in binary. Show all your working. The denary integer –32 is stored as a two’s complement integer. Calculate the two’s complement integer that would be stored. Show all your working. ,  ,
0478_s24_qp_12
THEORY
2024
Paper 1, Variant 2
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Computers use a character set to convert text into binary. One character set that can be used is ASCII. Each letter in ASCII can also be represented as a denary value. The word BUS has the denary values: B U S Convert the denary values into 8-bit binary. Each letter in ASCII can also be represented as a hexadecimal value. The word KEY has the 8-bit binary values: K E Y Convert the three 8-bit binary values into hexadecimal. Give three other uses of hexadecimal notation in computer science. State two benefits of using hexadecimal notation to represent binary values. Benefit 1 Benefit 2
0478_w18_qp_12
THEORY
2018
Paper 1, Variant 2
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Ron is attending a music concert. He has bought three tickets. Each ticket number is displayed as a hexadecimal number. Complete the table to show the 12-bit binary values and the Denary values for each Hexadecimal ticket number. Hexadecimal ticket number 12-bit binary value Denary value 1A9 20C Working space Each ticket also has a QR code. The QR code is scanned at the entrance to the venue. A person can only enter the venue with a valid QR code that allows entry. When a person enters, a count is incremented to show how many people have entered the venue. Explain how the system scans the QR code, checks if a person can enter and counts how many people have entered.
0478_w20_qp_11
THEORY
2020
Paper 1, Variant 1
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Questions Discovered
71