JEE Advanced2007PhysicsAtomic PhysicsActual
The largest wavelength in the ultraviolet region of the hydrogen spectrum is 122 ~nm . The smallest wavelength in the infrared region of the hydrogen spectrum (to the nearest integer) is
Options
- A802 ~nm
- B823 ~nm
- C1882 ~nm
- D1648 ~nm
Correct answer
B. 823 ~nm
Step-by-step solution
The series in U-V region is Lymen series. Longest wavelength corresponds to minimum energy which occurs in transition from n=2 to n=1 . 122= 1 R ( 1 1^2 - 1 2^2 ) The smallest wavelength in the infrared region corresponds to maximum energy of Paschen series. = 1 R ( 1 3^2 - 1 ) Solving Eqs. (i) and (ii), we get Correct option is (b). =823.5 ~nm