To get the number of unstable atoms:
Column 3: take 900 - 90 = 810 The numbers from column 2
To get the Number of decayed atoms:
take the 810 * 10% = 810 * .1 = 81
Follow the pattern for the rest of the table.
Wavelength = 1/frequency thus wavelength =1/30000
Silicon is used in the manufacturing of microchips and is also used in motherboards. We use it in our daily lives. It is a high tech element.
See this. I hope you find your answer