clear
//Given
Rh=1.097*10**7
n2=4.0
n1=3.0

//Calculation
lm=1/(Rh*(1/n1**2-1/n2**2))
lm1=9/Rh

//Result
printf("\n Wavelength is %0.1f  nm. This wavelength is in infrared part",lm1*10**9)