Question

Calculate the change in angular momentum of electron when it jumps from 3rd orbit to 1st orbit in hydrogen atom.
(Ans : 2.111 x 10⁻³⁴Js or kgm²s⁻¹)

Answer 1

Answer:2.111 ×10^-34Js

Explanation:

We know that,

Angular momentum =L=mvr=nh/2 × 3.14 i.e pi

So,

n=3

L = 3h/2×3.14 =1.5h/3.14 ....(1)

Similarly, n=1

L = 1h/2×3.14 =0.5h/3.14 ....(2)

So, (1)-(2);we get

h/3.14=(1.5-0.5)

After solving,

L=2.111 ×10^-34Js (Use log book for calculations)

Answer 2

Dear Student,

◆ Answer -

∆L = 2.107x10⁻³⁴ J.s

◆ Explanation -

Angular momentum of electron in nth orbit of hydrogen is given by -

L = nh / 2π

For 1st orbit,

L1 = (1 × 6.62×10⁻³⁴) / (2 × 3.142)

L1 = 1.053×10⁻³⁴ J.s

For 3rd orbit,

L3 = (3 × 6.62×10⁻³⁴) / (2 × 3.142)

L3 = 3.16×10⁻³⁴ J.s

When electron jumps from 3rd orbit to 1st orbit -

∆L = L3 - L1

∆L = 3.16×10⁻³⁴ - 1.053×10⁻³⁴

∆L = 2.107x10⁻³⁴ J.s

Hope this helps..