How To Calculate RCF

RCF Equation:

\[ RCF = 1.118 \times 10^{-5} \times r \times (RPM)^2 \]

Relative Centrifugal Force (RCF):

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1. What Is Relative Centrifugal Force?

Relative Centrifugal Force (RCF) is the measurement of the gravitational force applied in a centrifuge. It represents the actual force experienced by samples during centrifugation and is expressed in multiples of gravitational acceleration (g).

2. How Does The Calculator Work?

The calculator uses the RCF equation:

\[ RCF = 1.118 \times 10^{-5} \times r \times (RPM)^2 \]

Where:

\( RCF \) — Relative centrifugal force (g)
\( r \) — Radius in centimeters (cm)
\( RPM \) — Rotations per minute (rev/min)
\( 1.118 \times 10^{-5} \) — Conversion constant

Explanation: The equation converts rotational speed (RPM) to actual gravitational force, accounting for the radius of rotation. The force increases with the square of the RPM, making higher speeds exponentially more powerful.

3. Importance Of RCF Calculation

Details: Accurate RCF calculation is essential for reproducible centrifugation protocols across different equipment. Using RCF instead of RPM ensures consistent results regardless of centrifuge model or rotor size.

4. Using The Calculator

Tips: Enter the radius from the center of rotation to the sample in centimeters, and the rotational speed in RPM. Ensure both values are positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: Why use RCF instead of RPM?
A: RCF provides a standardized measure of force that accounts for rotor radius, ensuring consistent results across different centrifuges, while RPM alone doesn't indicate the actual force applied.

Q2: How do I measure the radius?
A: Measure from the center of the centrifuge rotor to the bottom of the sample tube when it's in the horizontal position during rotation.

Q3: What is a typical RCF range for common applications?
A: Routine applications range from 200-20,000 g, with ultracentrifugation reaching up to 1,000,000 g for specialized separations.

Q4: Can I convert RCF back to RPM?
A: Yes, the formula can be rearranged: \( RPM = \sqrt{\frac{RCF}{1.118 \times 10^{-5} \times r}} \)

Q5: Why does the force increase with the square of RPM?
A: Centrifugal force is proportional to the square of angular velocity, which relates directly to RPM squared in the calculation.