1. ## URGENT physics question please.

A diffraction grating (with 10,000 lines per cm) is held 2 meters from a Hydrogen lamp (lamp which emits
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2. Originally Posted by InsPiRation
A diffraction grating (with 10,000 lines per cm) is held 2 meters from a Hydrogen lamp (lamp which emits
Hydrogen’s spectrum). As you look through the diffraction grating a blue line is observed to lie 1.11 meters on either
side of the lamp.
a) At what distance from the lamp (central maximum) will the second occurrence of this blue line be observed at?
Bohr’s model of the hydrogen atom states that the energy levels are given by the formula E = -13.6 eV/n2, where n labels
the energy state of the hydrogen atom.
b) What transition (from initial n to final n) does this blue line correspond to?
c) What series does this line belong to?
You will find the relevant theory in any relevant textbook.

a) $1.11 = \frac{(1)(\lambda)(2)}{10^{-6}} \Rightarrow \lambda = 555 \, \text{nm}$. Therefore $X_2 = \frac{(2)(555 \times 10^{-9})(2)}{10^{-6}}$ m.