Geometric/arithmetic question (1 Viewer)

[kpad5991]

When light passes through one sheet of very thin glass, it's intensity is reduced by 3%. What is the minimum number of sheets that will reduce the intensity of the light below 1%?

What is the first, second and third term?
Is this a geometric or arithmetic progression ?

 

[braintic]

When light passes through one sheet of very thin glass, it's intensity is reduced by 3%. What is the minimum number of sheets that will reduce the intensity of the light below 1%?

What is the first, second and third term?
Is this a geometric or arithmetic progression ?

For a start, this is 2 unit, not 4.

97% of the light gets through the first sheet.
97% of THAT transmitted light gets through the second sheet. So 0.97^2 of the light incident on the first sheet gets through the two sheets.
Following this through, if there are n sheets then the fraction of light which gets through is 0.97^n.
So you need to solve 0.97^n < 0.01