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In hydrogen atom an electron makes a transition from 5th orbit to 3rd orbit. The change in the angular momentum for this electron is _________.

Asked in GUJCET 2023 · Postulates, radius, speed and angular momentum

• (1) h/π
• (2) h/(2π)
• (3) (3h)/π
• (4) (5h)/π

Step-by-step solution

Why the other options are wrong

• (2) h/(2π) is the change for a jump of one orbit; here the electron drops two orbits, from n=5 to n=3.
• (3) comes from no single slip produces (3h)/π. Sanity check: the final orbit alone has L₃=(3h)/(2π), and the change is L₅-L₃=(2h)/(2π)=h/π.
• (4) comes from no single slip produces (5h)/π. Sanity check: the starting orbit alone has L₅=(5h)/(2π), and the change is only ((5-3)h)/(2π)=h/π.

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