Question

what is the longest wavelength of Balmer series in armstrom unit

Answer 1

700 nm is the longest wavelength of Balmer series

Answer 2

Answer:

Explanation:

According to Balmer formula

ṽ=1/λ = RH[1/n12-1/n22]

For the Balmer series, ni = 2.

Thus, the expression of wavenumber(ṽ) is given by,

Wave number (ṽ) is inversely proportional to wavelength of transition. Hence, for the longest wavelength transition, ṽ has to be the smallest.

For ṽ to be minimum, nf should be minimum. For the Balmer series, a transition from ni = 2 to nf = 3 is allowed. Hence, taking nf = 3,we get:

ṽ= 1.5236 × 106 m–1

Wavelength and energy are inversely proportional so as the energy increase the wavelength decrease and vice versa. All the balmer series of hydrogen atom has n=2

Calculating the wavelenght using rydberg equation and the rydberg's equation is:

For longer wavelength:

=

= 1.52

Therefore

labda  = 6.56*m = 656nm