According to Bohr's theory the moment of momentum of an electron revolving in second orbit of hydrogen atom will be

Options

A. `(h)/(pi)`
B. `2pih`
C. `(2h)/(pi)`
D. `(pi)/(h)`

Explanation

To find the angular momentum of an electron revolving in the second orbit of a hydrogen atom according to Bohr's theory, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Bohr's Theory**: According to Bohr's model of the atom, the angular momentum (L) of an electron in a particular orbit is quantized and is given by the formula:
\[ L = n \frac{h}{2\pi} \]
where \( n \) is the principal quantum number (orbit number) and \( h \) is Planck's constant.

2. **Identify the Principal Quantum Number**: For the second orbit, the principal quantum number \( n \) is 2.

3. **Substitute the Value of n**: Plugging \( n = 2 \) into the formula for angular momentum:
\[ L = 2 \frac{h}{2\pi} \]

4. **Simplify the Expression**: The 2 in the numerator and the 2 in the denominator will cancel out:
\[ L = \frac{h}{\pi} \]

5. **Conclusion**: Therefore, the angular momentum of the electron revolving in the second orbit of a hydrogen atom is:
\[ L = \frac{h}{\pi} \]

### Final Answer:
The moment of momentum of an electron revolving in the second orbit of a hydrogen atom is \( \frac{h}{\pi} \).

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