Question

The angular momentum of an electron in the n^th orbit of hydrogen atom is _________.
1. \( { 2π\over nh}\)
2. \( {h \over 2πn}\)
3. \( {nh \over 2π}\)
4. \( {nh 2π}\)

Answer 1

Correct Answer - Option 3 : \( {nh \over 2π}\)

CONCEPT:​

• Angular momentum: the quantity of a rotating body, which is the product of its moment of inertia and its angular velocity.

Angular momentum (L) = m v r

where m is the mass of the body, v is velocity and r is the distance from the rotating point.

• Bohr proposed that the angular momentum L of an electron in its orbit is quantized and it has only specific discrete values.

From Bohr's Model of Atom, n^th orbit has angular momentum:

​angular momentum (L) = mvr = \( {nh \over 2π}\)

where n is the orbit number, h is plank constant.

CALCULATION:

• From Bohr's Model of Atom, nth orbit has angular momentum

​angular momentum (L) = \( {nh \over 2π}\)

• So the correct answer is option 3.