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Relative Centrifugal Force Formula:
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Relative Centrifugal Force (RCF), measured in g-force (×g), represents the gravitational force experienced by samples in a centrifuge. It's a more accurate measure of centrifugation intensity than RPM alone, as it accounts for the rotor radius.
The calculator uses the RCF formula:
Where:
Explanation: The formula converts rotational speed (RPM) to gravitational equivalent force, allowing for standardized comparisons between different centrifuges and rotors.
Details: Accurate RCF calculation is essential for reproducible experimental results, protocol standardization across different laboratories, and ensuring proper separation of samples based on their sedimentation coefficients.
Tips: Enter the rotor radius in centimeters (measure from center of rotation to sample) and the RPM value. Both values must be positive numbers for accurate calculation.
Q1: Why use RCF instead of RPM?
A: RCF provides a standardized measure of centrifugation force that accounts for rotor geometry, allowing for reproducible results across different centrifuges and rotors.
Q2: How do I measure rotor radius?
A: Measure from the center of the centrifuge rotor to the bottom of the sample tube holder when the rotor is in horizontal position, or to the middle of the tube for fixed-angle rotors.
Q3: What are typical RCF values used in laboratories?
A: Typical ranges vary: low-speed (200-2,000 ×g), medium-speed (2,000-20,000 ×g), high-speed (20,000-80,000 ×g), and ultracentrifugation (>80,000 ×g).
Q4: Can I convert RCF back to RPM?
A: Yes, using the formula: \( RPM = \sqrt{\frac{g}{1.118 \times 10^{-5} \times r}} \)
Q5: Does tube position affect RCF calculation?
A: Yes, for swinging bucket rotors, use the maximum radius. For fixed-angle rotors, use the average or effective radius depending on the application.