Question

Calculate the longest wavelength in in the Balmer series of singly Ionised helium .  Select the correct answer.​

Answer 1

Answer:

Solutions

Explanation:

Answer 2

Answer:

Since wavelength and energy are inversely related, the longest wavelength would be produced by the lowest amount of energy. That would be by the electron falling from from n = 3 (ni) to n = 2 (nf). (All Balmer series lines have nf = 2). lambda = 1 / (1.52 x 10^6 m) = 6.56 x 10^-7 m = 656 nm . . .that's a RED lineLongest wavelength is emitted in Balmer series if the transition of electron takes place from n2=3 to n1=2.

∴ Longest wavelength in Balmer series λL1=R(221−321)

Or λs=5R36

⟹ λs=5×1.097×10736=656.3nm

Explanation: