Physical

Centrifuge k-factor: practice problems

Work out the result for centrifuge k-factor. Every answer here is computed by the same tested calculator the rest of the site uses, so a solution can never drift away from the maths.

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Problem 1 Centrifuge k-factor

Work out the result for centrifuge k-factor.

  • r max (cm): 9.5
  • r min (cm): 6
  • Speed (rpm): 10000
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This rotor has a k-factor of 1163.

  1. Radius ratio: rmax / rmin = 1.583
  2. Natural log of ratio: ln(rmax / rmin) = 0.4595
  3. Clearing factor: k = 2.53e11 * 0.4595 / (10000)^2 = 1163

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Problem 2 Centrifuge k-factor

Work out the result for centrifuge k-factor.

  • r max (cm): 9
  • r min (cm): 4
  • Speed (rpm): 10000
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This rotor has a k-factor of 2052.

  1. Radius ratio: rmax / rmin = 2.25
  2. Natural log of ratio: ln(rmax / rmin) = 0.8109
  3. Clearing factor: k = 2.53e11 * 0.8109 / (10000)^2 = 2052

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Problem 3 Centrifuge k-factor

Work out the result for centrifuge k-factor.

  • r max (cm): 8
  • r min (cm): 5
  • Speed (rpm): 10000
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This rotor has a k-factor of 1189.

  1. Radius ratio: rmax / rmin = 1.6
  2. Natural log of ratio: ln(rmax / rmin) = 0.47
  3. Clearing factor: k = 2.53e11 * 0.47 / (10000)^2 = 1189

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Problem 4 Centrifuge k-factor

Work out the result for centrifuge k-factor.

  • r max (cm): 9.5
  • r min (cm): 5
  • Speed (rpm): 10000
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This rotor has a k-factor of 1624.

  1. Radius ratio: rmax / rmin = 1.9
  2. Natural log of ratio: ln(rmax / rmin) = 0.6419
  3. Clearing factor: k = 2.53e11 * 0.6419 / (10000)^2 = 1624

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Problem 5 Centrifuge k-factor

Work out the result for centrifuge k-factor.

  • r max (cm): 13
  • r min (cm): 5
  • Speed (rpm): 50000
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This rotor has a k-factor of 96.7.

  1. Radius ratio: rmax / rmin = 2.6
  2. Natural log of ratio: ln(rmax / rmin) = 0.9555
  3. Clearing factor: k = 2.53e11 * 0.9555 / (50000)^2 = 96.7

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Problem 6 Centrifuge k-factor

Work out the result for centrifuge k-factor.

  • r max (cm): 9.5
  • r min (cm): 3
  • Speed (rpm): 10000
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This rotor has a k-factor of 2916.

  1. Radius ratio: rmax / rmin = 3.167
  2. Natural log of ratio: ln(rmax / rmin) = 1.153
  3. Clearing factor: k = 2.53e11 * 1.153 / (10000)^2 = 2916

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Problem 7 Centrifuge k-factor

Work out the result for centrifuge k-factor.

  • r max (cm): 10.5
  • r min (cm): 5
  • Speed (rpm): 40000
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This rotor has a k-factor of 117.3.

  1. Radius ratio: rmax / rmin = 2.1
  2. Natural log of ratio: ln(rmax / rmin) = 0.7419
  3. Clearing factor: k = 2.53e11 * 0.7419 / (40000)^2 = 117.3

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Problem 8 Centrifuge k-factor

Work out the result for centrifuge k-factor.

  • r max (cm): 13
  • r min (cm): 5.5
  • Speed (rpm): 40000
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This rotor has a k-factor of 136.

  1. Radius ratio: rmax / rmin = 2.364
  2. Natural log of ratio: ln(rmax / rmin) = 0.8602
  3. Clearing factor: k = 2.53e11 * 0.8602 / (40000)^2 = 136

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Problem 9 Centrifuge k-factor

Work out the result for centrifuge k-factor.

  • r max (cm): 9
  • r min (cm): 5.5
  • Speed (rpm): 10000
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This rotor has a k-factor of 1246.

  1. Radius ratio: rmax / rmin = 1.636
  2. Natural log of ratio: ln(rmax / rmin) = 0.4925
  3. Clearing factor: k = 2.53e11 * 0.4925 / (10000)^2 = 1246

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Problem 10 Centrifuge k-factor

Work out the result for centrifuge k-factor.

  • r max (cm): 9
  • r min (cm): 5
  • Speed (rpm): 10000
Show the answer and the working

This rotor has a k-factor of 1487.

  1. Radius ratio: rmax / rmin = 1.8
  2. Natural log of ratio: ln(rmax / rmin) = 0.5878
  3. Clearing factor: k = 2.53e11 * 0.5878 / (10000)^2 = 1487

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More physical practice

Same topic, different calculation

RPM ⇄ RCF

Convert centrifuge speed to g-force using the rotor radius.

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Open the Centrifuge k-factor calculator