Stars/ Waves Diffraction Grating

Question 1

How ti find the uncertainty in lambda, what ti say for each

How to conclude uncertainty in lambda = uncertainty in theta

Answer 1

• there is no uncertainty in n
• uncertainty in d must be negligible

Uncertainty of sin theta = U theta (as functions have no effect)

Thus uncertainty in lambda = uncertainty in theta

Question 2

Okay so now how to calculate uncertainty in theta?

Answer 2

Need an equation
Could be arc sin or arc tan trig , however as you know functions don’t do anything, it’s gonna = uncertainty in trig expression

== need to pick the one that has ACTUAL MEAUSREMENTS, can’t find uncertainty in a calculated value (unless gradient is used)

look at what you have, and pick. If OPPSITE and adjacent. = tan

Find uncertainty in this (dividing so add) and so conclude uncertainty must be this

But must say uncertainty in sin theta or tan theta, not THETA ALONS

Question 3

Final how to say for uncertainty in lambda = uncertainty in what’s?

Answer 3

Uncertainty in sin theta (even if used tan ) approach

Easy- don’t lack

Question 4

Also try not to use sin theta, work out theta first then sin

Answer 4

So use tan then sin, they like better