End of Unit Assessment- Data Representation

What is binary?

Binary is a base-2 number system using only 0 and 1.

What is denary?

Denary is a base-10 number system using digits 0-9.

What is hexadecimal?

Hexadecimal is a base-16 number system using 0-9 and A-F.

Why do computers use binary?

Because hardware can easily represent on/off states.

What is a bit?

A bit is a single binary digit (0 or 1).

What is a nibble?

A nibble is 4 bits.

What is a byte?

A byte is 8 bits.

How many values can a byte represent?

256 different values.

How do you convert binary to denary?

Multiply each bit by its place value and add the results.

How do you convert denary to binary?

Repeatedly divide by 2 and read remainders bottom to top.

What does hexadecimal A represent?

10 in denary.

What does hexadecimal F represent?

15 in denary.

Why is hexadecimal used?

To shorten binary and make values easier for humans to read.

How many bits are in one hexadecimal digit?

4 bits.

What is binary addition?

Adding binary numbers using base-2 rules.

What is 1 + 1 in binary?

10.

What is binary subtraction?

Subtracting binary numbers using borrowing.

Why is binary arithmetic important?

Because computers perform calculations using binary.

What is ASCII?

A character set using 7 bits to represent characters.

How many characters can ASCII represent?

128 characters.

What is a limitation of ASCII?

It only supports English characters.

What is Unicode?

A character set that supports characters from all languages.

Why does Unicode need more storage than ASCII?

Because it uses more bits per character.

What is a bitmap image?

An image made up of individual pixels.

What is a pixel?

The smallest unit of an image.

What is image resolution?

The number of pixels in an image (width × height).

How does higher resolution affect quality?

It increases image quality.

How does higher resolution affect file size?

It increases file size.

What is colour depth?

The number of bits used to represent the colour of each pixel.

How does higher colour depth affect file size?

It increases file size.

What is the image file size formula?

Width × height × colour depth.

How is sound represented in computers?

By sampling sound waves and storing them as binary.

What is sampling?

Measuring sound at regular intervals.

What is sample rate?

The number of samples taken per second.

What is sample resolution?

The number of bits used per sample.

How does higher sample rate affect quality?

It increases sound quality.

How does higher sample rate affect file size?

It increases file size.

What is the sound file size formula?

Sample rate × sample resolution × duration.

What is data compression?

Reducing file size.

Why is data compression used?

To save storage space and bandwidth.

What is lossy compression?

Compression where data is permanently removed.

What is an advantage of lossy compression?

Much smaller file size.

What is a disadvantage of lossy compression?

Loss of quality.

Give an example of lossy compression use.

Music or images.

What is lossless compression?

Compression where no data is lost.

What is an advantage of lossless compression?

Original file can be perfectly restored.

What is a disadvantage of lossless compression?

File size is larger than lossy.

Give an example of lossless compression use.

Text files or program files.

What is Run Length Encoding (RLE)?

A lossless compression technique.

How does RLE work?

Stores repeated values as one value and a count.

When does RLE work best?

When there are long runs of the same data.

Why is RLE not always effective?

It can increase file size if data does not repeat.

Why does higher quality usually increase file size?

Because more bits are needed to store data.

Why does colour depth affect image quality?

More bits allow more colours.

Why does sample resolution affect sound quality?

More bits give more accurate sound values.

Why is compression important for streaming?

It reduces data transfer requirements.

What does 1 byte equal in bits?

8 bits.

What base is binary?

Base 2.

What base is hexadecimal?

Base 16.