## Material Thickness

1. A conductive sheet of material has a CSA of 10mm x 20mm. Reisistivity of 103 (10 to the 3, 10,000) ohms M. Calculate thickness of the material required to give resistance of 5k ohms

2. Ro = RA/l , where l would be thickness, l = RA/Ro

3. Thickness = 5,000 x 0.2 / 10,000 = o.1m therefore 100m

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 Mentor Blog Entries: 10 There are some problems with your calculation:103 is not 10,000. The area is not 0.2 (is that supposed to be in m2?). Try converting the mm values to meters first. Remember, 1 mm is 10-3 m.

 Quote by Redbelly98 There are some problems with your calculation:103 is not 10,000. The area is not 0.2 (is that supposed to be in m2?). Try converting the mm values to meters first. Remember, 1 mm is 10-3 m.
Thanks:

Thickness = 5,000 x 0.0002/ 1,000 = 1 x 10-3m therefore 1mm

or do I have to sq the .ooo2 giving:

=5,000 x 4x10-8 / 1,000 = 2 x 10-7

Mentor
Blog Entries: 10

## Material Thickness

One of those is correct! Here are 2 questions to help you decide which:

1. How did you get the 0.0002 value for the area, and therefore what are the units associated with this value?

2. Are these units (from my previous question) correct units for an area, or would you need to square the units to to get an area?

Note: correct units for area can be expressed as m2, m·m, mm2, or mm·mm.

 Quote by Redbelly98 One of those is correct! Here are 2 questions to help you decide which: 1. How did you get the 0.0002 value for the area, and therefore what are the units associated with this value? 2. Are these units (from my previous question) correct units for an area, or would you need to square the units to to get an area? Note: correct units for area can be expressed as m2, m·m, mm2, or mm·mm.
Hi, thanks for the reply, think I am having a christmas moment.
The area should be 10mm x 20mm = 200mm in m 200 x 10-3 therefore 0.2m
Thickness = 5,000 x 0.2/ 1,000 = 1mm

How does this seem

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Blog Entries: 10
 Quote by Kev1n Hi, thanks for the reply, think I am having a christmas moment. The area should be 10mm x 20mm = 200mm ...