1. A measurement of 2.50 mm is equivalent to ...
QUESTION:
A measurement of 2.50 mm is equivalent to ...
A. 2.50x106 nm, B. 2.50x10-9 nm,
C. 2.50x10-6 nm, D. 2.50x109 nm
General strategy for converting units:
(known amount) x (conversion factor)
Conversion factor = ratio of equivalent amounts; set up so that original unit cancels out.
A measurement of 2.50 millimeters is equivalent to how many nanometers?
PAUSE
CLICK The general strategy for converting units is to multiply the known amount
by a conversion factor.
The conversion factor is just the ratio of equivalent amounts. We need to set up
the conversion factor so that the original unit cancels out.
CLICK
CONTINUED ON NEXT SLIDE

2. A measurement of 2.50 mm is equivalent to ...
QUESTION:
A measurement of 2.50 mm is equivalent to ...
A. 2.50x106 nm, B. 2.50x10-9 nm,
C. 2.50x10-6 nm, D. 2.50x109 nm
10-3 m
1 nm
2.50 mm x x
= 2.50x106 nm
1 mm
10-9 m
You should know what the SI prefixes mean. The prefix milli means 1/1000, or Therefore, we can write
a conversion factor with
1 millimeter in the numerator and 10-3 meter in the denominator.
HIGHLIGHT 1 mm/10-3 m
Or we can write a conversion factor with 10-3 meter in the numerator and 1 millimeter in the denominator
HIGHLIGHT 10-3 m / 1 mm
We can use these conversion factors to convert millimeters to meters, or meters to millimeters
CLICK
Similarly, the SI prefix nano means Therefore, we can write a conversion factor with
1 nanometer in the numerator and 10-9 m in the denominator.
HIGHLIGHT 1 nm / 10-9 m
or we can write a conversion factor with 10-9 m in the numerator and 1 nanometer in the denominator.
We can use these conversion factors to convert nanometers to meters, or meters to nanometers.
The question is asking us to convert millimeters to nanometers, and none of the conversion factors we have
here allows us to do that. However, it should be easy to see that we can accomplish the conversion by
first converting millimeters to meters
then convert the result, ...which is in meters..., to nanometers.
So, here’s how it’s done.
Start with the known measurement millimeters
Multiply it by a conversion factor to convert millimeters to meters.
CLICK CLICK CLICK THen multiply by a conversion factor to convert meters to nanometers.
CLICK CLICK CLICK CLICK
This gives us an answer of 2.50x106 nanometers.
Therefore, the correct answer is A.
We express our answer to significant digits in the answer because the original measurement, 2.50 millimeters, has two significant figures.
All the numbers in the conversion factors are exact and have no uncertainty.
CLICK PAUSE
END RECORDING
mm  m
m  mm
nm  m
m  nm
1 mm m nm m
10-3 m mm m nm

3. Video ID: 1A-5-3 © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Narrator: Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08