# Scientific Notation

Measuring physical phenomena in the real world we enevitably encounter numbers of large magnitude. The estimated (insert example here) is 1,000000000 * n zeros while the time taken for a photon of light to cross the radius of an atom is 0.0000000000000000000000000000000000000001. Clearly, performing calculations with such unweildy numbers is entirely impractical. Therefore, we need 'short-hand' method for writing these numbers. For number with upto 18 significant figures (18 zeros to the right). We can use the prefixes. For anything that falls between the gaps, we write the number of zeros as the index of a power of 10.

For example, 1,000,000 is 1 x 106 as there are 6 zeros after the 1.

and for 0.1 is 1 x 10-1. 100 = 1.

## Questions

Write the following numbers using scientific notation

• The age of the universe is approximately 14,000,000,000 years
• Using the physics we know today, we can calculate what happened 0.000, 000, 000, 000,000, 000, 000, 000, 000, 000, 000, 000, 000, 001 seconds after the 'big-bang'.
• There are number of atoms in a metre3 is approximately, 1,000,000,000,000,000,000,000,000,000,000,000,000.
• One mole of atoms contains 624, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000,000, 000, 000, 000, 000 ,000.
• An atomic nucleus is approximately 0.000,000,000,000,01 metres.
• Your voice is amplified 1,000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000,000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000,000, 000, 000, 000, 000, 000 times by the valves when making a long distance phone call from california to New-York in 1950s.
• The redshift on a quasi is measured as 10 billion light-years. In meters this is 9,470,000,000,000,000,000,000,000,000 metres.
• Google is one of the most popular search engines, but a Googol is also the name given to the number: 10,000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000.