The wavelength of a line in the emission line spectrum of hydrogen caused by the transition of an electron from an orbital with n = 11 to an orbital with n = 7 can be calculated using the Rydberg formula.
The Rydberg formula for the wavelength of the spectral line is:
1/λ = R(1/n₁² - 1/n₂²)
Where λ is the wavelength, R is the Rydberg constant, and n₁ and n₂ are the initial and final quantum numbers of the electron's orbit, respectively.
Substituting the given values of n₁ and n₂ into the equation and solving for λ:
1/λ = R(1/11² - 1/7²)
1/λ = R(0.0081 - 0.0370)
λ = 1/(R(0.0370 - 0.0081))
Since we don't know the value of R, we don't have enough information to calculate the wavelength of the line.