The radius of second Bohr’s orbit of Hydrogen atom is:

Options

A. a-0.053 nm
B. b-`(0.053)/(4)nm`
C. c-`0.053 xx4nm`
D. d-`0.053 xx20nm`

Explanation

To find the radius of the second Bohr's orbit of a hydrogen atom, we can use the formula for the radius of the nth Bohr orbit:

### Step-by-step Solution:

1. **Identify the Formula**:
The formula for the radius of the nth Bohr orbit is given by:
\[ R_n = R_0 \frac{n^2}{Z} \]
where:
- \( R_n \) is the radius of the nth orbit,
- \( R_0 \) is the radius of the first orbit (approximately \( 0.0529 \) Å),
- \( n \) is the principal quantum number (the orbit number),
- \( Z \) is the atomic number of the atom.

2. **Substituting Values**:
For hydrogen, the atomic number \( Z = 1 \). We are interested in the second orbit, so \( n = 2 \).
\[ R_2 = R_0 \frac{2^2}{1} \]

3. **Calculate \( R_2 \)**:
Substituting \( R_0 = 0.0529 \) Å and \( n = 2 \):
\[ R_2 = 0.0529 \times \frac{4}{1} = 0.0529 \times 4 \]

4. **Perform the Multiplication**:
\[ R_2 = 0.0529 \times 4 = 0.2116 \text{ Å} \]

5. **Final Result**:
The radius of the second Bohr orbit of the hydrogen atom is approximately \( 0.2116 \) Å.