An online quiz asks students questions about computer science topics - Edexcel - GCSE Computer Science - Question 1 - 2018 - Paper 1
Question 1
An online quiz asks students questions about computer science topics.
(a) Images are used in some of the questions.
(i) An image is 300 pixels high and 200 pixels ... show full transcript
Worked Solution & Example Answer:An online quiz asks students questions about computer science topics - Edexcel - GCSE Computer Science - Question 1 - 2018 - Paper 1
Step 1
Construct an expression to calculate how many pixels are needed to represent this image.
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Answer
To calculate the total number of pixels in an image, you multiply the height by the width. Therefore, the expression will be:
300extpixels(height)imes200extpixels(width)
This results in:
60000exttotalpixels
Step 2
Describe how 24-bits are used to represent the colour in the file.
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Answer
A 24-bit colour depth means that each pixel in the image can represent a total of 16,777,216 different colours. This is achieved through the following combination:
Each pixel is represented by three primary colours: Red, Green, and Blue (RGB).
For each colour channel, 8 bits are allocated, leading to:
8 bits for Red
8 bits for Green
8 bits for Blue
The 24 bits collectively allow for a wide range of colours due to the combination of varying intensities of the three primary colours. Therefore, each pixel can display complex colours as a result of this bit allocation.