Femtometre is equal to

Options

A. Millionth part of a metre
B. Billionth part of a metre
C. Trilliionth part of a metre
D. Quadrillionth part of a metre.

Answer

To solve the question "Femtometre is equal to," we will follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition**:
- A femtometer (fm) is a unit of length in the International System of Units (SI).

2. **Origin of the Term**:
- The term "femtometer" comes from the Danish word "femten," which means "fifteen," and "metron," which means "measurement."

3. **Scientific Notation**:
- In scientific terms, one femtometer is equal to \(10^{-15}\) meters. This means that a femtometer is a very small unit of measurement.

4. **Interpret the Value**:
- Since \(10^{-15}\) is a very small number, it can also be described as a "quadrillionth" of a meter.

5. **Final Conclusion**:
- Therefore, one femtometer is equal to one quadrillionth of a meter.

### Final Answer:
- Femtometer is equal to \(10^{-15}\) meters or one quadrillionth of a meter.

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