If `a= (h)/(4 pi^(2)me^(2))` then correct expression for calculate the circumference of the first orbit of hydrogen atom is

Options

A. `sqrt(4h^(2)) pi a`
B. `2 pi r`
C. `sqrt(4) pi ha`
D. a and c are correct

Explanation

To solve the problem of finding the correct expression for the circumference of the first orbit of a hydrogen atom given the equation \( a = \frac{h}{4 \pi^2 m e^2} \), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Circumference Formula**:
The circumference \( C \) of a circle is given by the formula:
\[
C = 2 \pi r
...