Pixel Density & Component Accuracy: Does Width Matter?

[royshh]

The following question appeared on one of my exam papers.

A CCD of pixel density 10Mpixel (1cm^-2) is used to image a component of length 10cm.
Show how this does or does not meet the required accuracies of +/- 0.025mm.

A similar question was asked in a previous exam where the component's length was 10cm but a width of 1cm was also specified.

I would like to know whether or not both length and width are required in order to determine a solution.

I was of the impression that both dimensions would be needed but my lecturer disagrees.

Can anyone clarify the situation?

 

[member 553083]

In order to determine the accuracy of the CCD, both length and width must be taken into account. A CCD of pixel density 10Mpixel (1cm^-2) is not enough to determine the accuracy of the component of length 10cm. To calculate the required accuracy, the pixel size and the length and width of the component need to be known. In this case, since the width of the component is not given, it is impossible to determine the accuracy of the CCD.