Significant figures for spectral lines

[Nova Akhavan 2F]

For questions such as this: "Calculate the wavelength, in nanometers, of the spectral line produced when an electron in a hydrogen atom undergoes the transition from the energy level n=5 to the level n=2." How many significant figures should we include in our answers?

[Jack Amos 2I]

That is a really good question and I'm not really sure if there's a golden sig fig number that applies to all questions without defined measurements like this one. However, in regards to the midterm, I don't think you would need to worry about sig figs too much because of the multiple choice format. I'm assuming all the choices you are given to choose from will all have the same amount of sig figs.

[cecilia1F]

Hello,
The number of significant figures in the answer is determined by the number of significant digits in each of the numbers that you use to get to your solution. A good way to approach sig figs, I think, is to consider the number with the lowest number of significant figures as a type of limiting agent. If we have a number with only 2 sig figs, but every other number has 10, our answer can still only be known to certainty of two digits.

[N Kanuri 2E]

For questions such as these, where sig figs cannot be determined from the given information, I learned that it was best to use, at the minimum, three sig figs. Hope this helps!

[Brooke Gushiken 1B]

This is a really good question! It can be hard to tell when no values other than the n-values are given in the question. My TA told us that it's safest to round to three sig figs for your final answer when you feel unsure. I hope this helps!