According to Bohr’s theory, the angular momentum for an electron of `3^("rd")` orbit is:

Options

A. a.`3(h)/(2pi)`
B. b.`1.5(h)/(2pi)`
C. c.`9(h)/(2pi)`
D. d.`2(h)/(pi)`

Explanation

To find the angular momentum of an electron in the third orbit according to Bohr's theory, we can follow these steps:

### Step 1: Understand the formula for angular momentum in Bohr's theory
According to Bohr's theory, the angular momentum \( L \) of an electron in a given orbit is given by the formula:
\[ L = n \frac{h}{2\pi} \]
where:
- \( L \) is the angular momentum,
- \( n \) is the principal quantum number (the orbit number),
- \( h \) is Planck's constant.

### Step 2: Identify the value of \( n \)
For the third orbit, the principal quantum number \( n \) is equal to 3.

### Step 3: Substitute the value of \( n \) into the formula
Now we substitute \( n = 3 \) into the angular momentum formula:
\[ L = 3 \frac{h}{2\pi} \]

### Step 4: Simplify the expression
The expression for the angular momentum in the third orbit becomes:
\[ L = \frac{3h}{2\pi} \]

### Conclusion
Thus, the angular momentum for an electron in the third orbit according to Bohr’s theory is:
\[ L = \frac{3h}{2\pi} \]