Question

if you touch with needle it will not sense

if you touch with finger it will work .

I asked minimum surface area that it sense

probably 28.26mm² area required for finger on captivating display.


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Answer 1

22.26 mm ³ = area

•°• r = 3 mm

Needle will have = r < 0 = radius --- value will be below 0 .

r < 0 will not sense by captivating display it is too small.

That means a captivating display should

follow this rule = r > 0 , that is radius should be greater then 0 .

so minimum, radius requires = r > 0.

•°• Area = π r² ---- where r > 0