Homework for 13th Nov.

SQA 2007 Q17

17. John uses his digital camera to take photographs. It has a 512 Megabyte
memory card. His camera uses 16,777,216 colours and is set to a resolution of
3000 × 2000 pixels.
(a) (i) Calculate the file size of a single image. Your answer should be in
appropriate units. Show all working.
(ii) What is the maximum number of images of this size that can be
stored on John’s memory card?
(b) State two reasons why digital images are stored as JPEGs.
(c) He changes the setting in his camera to reduce the bit-depth.
Describe one effect that this will have.
(d) He connects his camera to his computer. One function of the interface is
the handling of status signals. Describe what is meant by the term “status
(e) There are a large number of pictures on his hard disk. The combined size
of all of his photographs is 3 Gb.
He can use a solid-state storage device or Rewritable DVD to take all of his
photographs to his chemist shop for printing. Recommend one of these
devices and justify your choice.