Data Types & Number Systems
What does it mean when we say that computers use analogue data and digital data?
Analogue = continuous
digital = 0s and 1s.
Convert the denary number 39 into an 8-bit binary number.
00100111
When the binary number 00101101 is shifted left logically by two places, what is the new binary value?
10110100
What are two ways a student could reduce the amount of data stored in an image file?
Lower resolution or apply compression.
What does a sample rate of 44,100 Hz mean for a sound file?
44,100 samples per second.
What is the difference between the denary number system and the binary number system?
Denary = base 10
Binary = base 2.
Convert the denary number 142 into an 8-bit binary number.
10001110
When the binary number 11100110 is shifted right logically by one place, what is the result?
01110011
What does color depth represent in a digital image?
Bits per pixel.
What does a sample size of 16 bits mean?
Number of bits per sample.
Why do computers store and process data using binary instead of denary?
Binary matches on/off circuits.
Convert the hexadecimal value 7A into an 8-bit binary number.
01111010
What is the 8-bit two’s complement representation of −23?
11101001
How many total pixels are in an image with a resolution of 200 × 200?
40,000 pixels.
What is the difference between lossy and lossless compression?
Lossy removes data; lossless keeps all data.
Why is hexadecimal often used in computing instead of binary?
Easier to read and less error-prone.
Convert the hexadecimal value C4 into an 8-bit binary number.
11000100
What is the result of adding the binary numbers 01101101 and 00110110?
10100011
A 200 × 200 image has a color depth of 16 bits. What is the file size in bytes?
80,000 bytes.
Give one example of a lossy format and one example of a lossless format.
MP3 / PNG.
Which value is the largest—
1 MiB
2048 KiB
1.4 MiB
or 1200 KiB—
and why?
2048 KiB (equals 2 MiB).
Convert the hexadecimal seat number 3AF into a 12-bit binary number.
001110101111
What happens to a binary number when a logical left shift of two places is performed?
Bits move left; zeros fill on the right.
Convert 80,000 bytes into KiB.
~78.1 KiB.
Why is lossless compression suitable for compressing sound files on a website?
Keeps full quality; fully reversible.