Solved: Value of Infinity for Hydrogen Atom Wavelength

[alexlee33]

[SOLVED] Value of inifinity?

Edit: typo in title (infinity); sorry

Homework Statement

What is the shortest wavelength of light emitted by an electron in the Brackett series of spectra lines of the hydrogen atom?

Homework Equations

1 / (wavelength) = RH ( (1/nu^2) - (1/nl^2) )

The Attempt at a Solution

1 / (wavelength) = 1.1 x 10^7 ( (1/4^2) - (1/(infinity?)^2) )

I am told the correct answer is 1.45 x 10^-6, but I cannot find it on my calculator because I am not sure what to put in the place of infinity.

Thanks!

 

[Dick]

One over a number infinitely close to infinity is infinitely close to zero. Just put in zero for the second term.

 

[Shooting Star]

The value of 1/x tends to zero as x tends to infinity.So, just put zero in place of 1/n1^2.

 

[Shooting Star]

(Sorry Dick, it seems we were typing at almost the same time.)

 

[alexlee33]

Thanks guys! :)