Using Rydberg’s formula, we have: v = R*[1/(n1^2) – 1/(n2^2)]

where v = frequency in cm^-1

R = Rydberg’s Constant = 109677.6 in cm^-1

n1 = 2 (Given)

n2 = 5 (Given)

Substituting the values, we get:

v = 109677.6 * [1/(2^2) – 1/(5^2)]

V = 109677.6 * [1/4-1/25]

v = 23,032.296 cm^-1 (Answer)

We know, wavelength = 1/frequency = 1/23032.296

Wavelength = 4.34 * 10^-5 cm (Answer)