iGCSE Computer Science: Data

Which of these input signals is a digital quantity?

• thermometer
• light sensor
• live music
• webcam

Computers use binary to represent data and programs because ...

• CPUs have millions of transistors which have two possible states
• Boolean logic only has two possible states
• Alan Turing suggested that in an academic paper
• it's a simpler system than decimal

What is the binary number 10101 in decimal?

• 1000

• 8

• 21

• 15

Computers use binary to represent data and programs because ...

• CPUs have millions of transistors which have two possible states

• Boolean logic only has two possible states

• Alan Turing suggested that in an academic paper

• it's a simpler system than decimal

Which is the binary version of 13?

• 1111

• 1110

• 1101

• 1001

With 6 bits of data how many different items of data can be represented?

• 64

• 32

• 128

• 6

How many bits are there in one byte of data?

• 8

• 2

• 10

• 1000

How many bits of data do you need to represent 512 different values?

• 9

• 512

• 8

• 10

Which is the character set of the hexadecimal number system?

• 0, 1

• 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

• 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16

• 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F

Why is the hexadecimal number system useful in Computer Science?

• Because 16 is a power of 2

• Because it shortens binary data by 75%

• Because computers originally only understood hexadecimal

• Because it's easier to do calculations in hexadecimal than binary