Question

the first lyman transition in the hydrogen spectrum has delta E = 10.2eV .The same energy change is observed in the second Balmer transition of :- .. a) Li +2 b) Li + c) He + d) Be 3+​

Answer 1

Answer:

(c)

Explanation:

refer to the photo attached

Answer 2

Answer:

c) He+

Explanation:

Delta of hydrogen spectrum = E = 10.2eV (Given)

For He+ ion -

1/λ = Z2R­H [1/n12 -1/n22]

= (2) 2RH [1/(2)2 – 1/(4)2] = RH 3/4 --- (1)

For hydrogen atom -

1/λ = RH [1/n12 -1/n22] --- (2)

Equating equation 1 and 2 we will get -

1/n²1 -1/n²1 = 3/4

Thus, n1 = 1 and n2 = 2

Hence, the transition n = 1 to n = 2 in hydrogen atom will have the same wavelength as the transition, n = 4 to n = 2 in He+ species. Thus, the same energy change is observed in the second Balmer transition of He +.