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## Homework Statement

For part d), how to show that they are inversely proportional to each other ? The mark scheme states:

"Correct calculation to check inverse proportionality. √h x cosϑ = k. Sensible comments relating to calculations to within 20% or their own value and suggested relation."

What do they mean by 20%?

## Homework Equations

Percentage uncertainty = (uncertainty/measured value) x100%

## The Attempt at a Solution

My values are,

√h = (2.95±0.1) cm, cos θ = 0.50. k1 = 2.95 x 0.50 = 1.475

√h = (2.30±0.1) cm, cos θ = 0.64, k2 = 2.30 x 0.64 = 1.472

I calculated the percentage difference of k,

((1.475-1.472) /1.472 ) x 100% = 0.2%

Then I calculated the uncertainty of √h = (0.1 / 2.30) x 100% = 4.3%

This is the method I followed from a textbook, so what does the 20% in the mark scheme represents ? Hope you all understand what I'm doing here..