How Text, Images and Sound are Stored

Digitisation refers to the process of converting information into a digital format, and it is important because it enables easier storage, access, and sharing of data.

• Digitisation refers to converting information into a digital format, making storage and sharing easier.

• Digitisation means printing documents for physical storage.

• Digitisation is the process of destroying old records.

• Digitisation is about creating handwritten copies of documents.

Answer explanation

The correct choice accurately defines digitisation as converting information into a digital format, which facilitates easier storage and sharing of data, aligning with the importance of digitisation.

Letters and symbols are stored in a computer as:

• Binary codes

• Decimal numbers

• Physical shapes

• Handwritten notes

Answer explanation

Letters and symbols are represented in computers using binary codes, which consist of 0s and 1s. This is the fundamental way data is processed and stored in digital systems, making 'Binary codes' the correct answer.

Standard ASCII uses how many bits to represent a character?

• 7

• 8

• 6

• 5

Answer explanation

Standard ASCII uses 7 bits to represent each character, allowing for 128 unique symbols. This is why the correct answer is 7, as it is the standard representation for ASCII characters.

Computers need Unicode in addition to ASCII because:

• Unicode can represent a much wider range of characters than ASCII.

• Unicode is faster than ASCII for all operations.

• ASCII supports all world languages, but Unicode does not.

• Unicode is only used for numbers, while ASCII is for letters.

Answer explanation

Unicode can represent a much wider range of characters than ASCII, which is limited to 128 characters. This allows Unicode to support multiple languages and symbols, making it essential for global communication.

A bitmap image stores a picture by:

• dividing the image into a grid of pixels, each with its own color value

• using mathematical formulas to describe shapes

• storing only the outlines of objects

• compressing the image into a single color

Answer explanation

A bitmap image represents a picture by dividing it into a grid of pixels, where each pixel has its own color value. This method allows for detailed and accurate image representation, unlike the other options listed.

A pixel is the smallest unit of a digital image, and it represents colour by combining values of red, green, and blue.

• A pixel is the smallest unit of a digital image, and it represents colour by combining values of red, green, and blue.

• A pixel is a large block that stores only black and white information.

• A pixel is a type of printer used to display colours on paper.

• A pixel is a software program that creates images without using colour.

Answer explanation

The correct choice accurately defines a pixel as the smallest unit of a digital image, which represents color by combining red, green, and blue values. The other options misrepresent what a pixel is.

Larger images or images with more colours take up more storage space because:

• They contain more data that needs to be stored.

• They are always compressed more efficiently.

• They use less memory than smaller images.

• They have fewer pixels to store.

Answer explanation

Larger images or those with more colors contain more data, as they have more pixels and color information to store. This is why they take up more storage space compared to smaller images.

The difference between bitmap and vector graphics is:

• Bitmap graphics are made of pixels, while vector graphics are made of paths.

• Bitmap graphics are always smaller in file size than vector graphics.

• Vector graphics cannot be resized without losing quality, but bitmap graphics can.

• Bitmap graphics are only used for text, while vector graphics are only used for photos.

Answer explanation

The correct choice highlights that bitmap graphics consist of pixels, making them resolution-dependent, while vector graphics are composed of paths, allowing for infinite scalability without quality loss.

A binary image is an image that uses how many bits per pixel?

• 1 bit per pixel

• 2 bits per pixel

• 8 bits per pixel

• 16 bits per pixel

Answer explanation

A binary image uses only two colors, typically black and white. To represent these two colors, only 1 bit per pixel is needed, where 0 can represent one color and 1 the other.

Select the option that lists three common image file formats and briefly describes one of them.

• JPEG, PNG, GIF; JPEG is commonly used for photographs and supports lossy compression.

• BMP, DOC, TXT; BMP is used for text documents and supports lossless compression.

• PDF, PNG, MP3; PNG is an audio format and supports lossless compression.

• GIF, XLS, JPEG; XLS is used for spreadsheets and GIF is used for high-quality print images.

Answer explanation

The correct choice is 'JPEG, PNG, GIF; JPEG is commonly used for photographs and supports lossy compression.' This accurately lists three common image formats and provides a correct description of JPEG.