In an atom the ratio of radius of orbit of electron to the radius of nucleus is

Options

A. `10^3`
B. `10^4`
C. `10^5`
D. `10^6`

Explanation

To solve the problem of finding the ratio of the radius of the orbit of an electron to the radius of the nucleus in an atom, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the given values**:
- The radius of the orbit of the electron, denoted as \( R_e \), is \( 10^{-10} \) meters.
- The radius of the nucleus, denoted as \( R_n \), is \( 10^{-15} \) meters.

2. **Set up the ratio**:
- We need to calculate the ratio \( \frac{R_e}{R_n} \).

3. **Substitute the values into the ratio**:
- Substitute \( R_e \) and \( R_n \) into the ratio:
\[ \frac{R_e}{R_n} = \frac{10^{-10}}{10^{-15}} \]

4. **Simplify the ratio**:
- When dividing powers of ten, we subtract the exponents:
\[ \frac{10^{-10}}{10^{-15}} = 10^{-10 - (-15)} = 10^{-10 + 15} = 10^{5} \]

5. **Conclusion**:
- The ratio of the radius of the orbit of the electron to the radius of the nucleus is:
\[ \frac{R_e}{R_n} = 10^{5} \]
- This means that the radius of the electron's orbit is \( 10^{5} \) times larger than the radius of the nucleus.

### Final Answer:
The ratio of the radius of the orbit of the electron to the radius of the nucleus is \( 10^{5} \).

---