If you perform dilutions 10^-1, 10^-2, and 10^-3, what is the dilution factor of the 10^-2 tube relative to the original culture?

If you perform dilutions 10^-1, 10^-2, and 10^-3, what is the dilution factor of the 10^-2 tube relative to the original culture?

• A. 10
• B. 100
• C. 1000
• D. 0.1

Answer: (B)

In serial dilutions, the exponent shows how much the concentration is reduced compared with the original culture. A 10^-2 dilution means one part sample in 100 total parts, a 100-fold dilution. So, relative to the original culture, the 10^-2 tube has been diluted by a factor of 100. Each tenfold step multiplies the dilution by 10, so two steps give 10 × 10 = 100. The other values correspond to different dilutions (10-fold or 1000-fold) or imply concentration rather than dilution, so they don’t fit as the relative dilution factor for the 10^-2 tube.

In serial dilutions, the exponent shows how much the concentration is reduced compared with the original culture. A 10^-2 dilution means one part sample in 100 total parts, a 100-fold dilution. So, relative to the original culture, the 10^-2 tube has been diluted by a factor of 100. Each tenfold step multiplies the dilution by 10, so two steps give 10 × 10 = 100. The other values correspond to different dilutions (10-fold or 1000-fold) or imply concentration rather than dilution, so they don’t fit as the relative dilution factor for the 10^-2 tube.