Marley wants to store a video he has created for his school project. He considers using a DVD or a Blu-ray to store the video. Explain two differences between a DVD and a Blu-ray.

Mark scheme

Marking points from the official mark scheme (May/June 2019). The mark or mark type is shown in brackets.

1. [2] Two from e.g.: DVD uses red laser/light whereas blu-ray uses blue/violet laser/light DVD has a smaller (storage) capacity // Blu-ray has a larger (storage) capacity DVD has two layers (of polycarbonate) whereas Blu-ray disks have a single layer (of polycarbonate) DVD has a slower transfer rate (of approximately 10 mbps) // Blu-ray has a faster transfer rate (of approximately 36 mbps)
2. [3] 2 marks for any two correct stages of working, 1 mark for correct answer. 500 * 300 * 10 // 150 000 *10 * 8 then ÷ 8 (anywhere in the process) 1500 000 ÷ 1024 ÷ 1024 // 1 500 000 ÷ 1 048 576 = 1.43 MB
3. [4] Four from: Rollers are used to move the paper through the printer Nozzles spray/drop/jet ink onto the paper Ink jets/print head/nozzles are moved across the paper (to distribute the ink) Different colour inks are mixed to create required colours Technology could be piezoelectric Technology could be thermal bubble Ink is heated and expands/evaporates into a bubble Bubble is pushed through the nozzle on to the paper then the bubble collapses Electrical current is applied to a crystal which makes it vibrate which forces a droplet of ink through the nozzle