'Meter' is the standard of length in the metric and SI systems. One meter is about 39 and 1/3 inches. 'Nanometer' is one billionth part of one meter.
0000000039 meters in one nanometer.
692.1 nanometers is equivalent to 0.0000006921 meters, or 6.921 x 10^-7 meters.
520 nanometers=5.2 × 10-7 meters
Multiply by 10^-9