The plastic notes have the life spam of 5 years which is 5 times greater than normal notes. It doesn't get dirty. RBI destroys thousands of currency notes every day.
Friday, March 19, 2010
Plastic Currency Notes - Reserve Bank of INDIA
Reserve Bank of India (RBIpublished Rupees10 polymer notes recently. The note is made of polymers (plastic) in the place of normal cotton notes. Yes the notes we use today are made of pure cotton not paper.
Thursday, March 11, 2010
Why the gold smiths add material to the gold to make ornaments
The pure gold is not useful for doing the ornaments, the pure gold is so delicate. They add materials of silver, copper, Nickel, Zinc to bring strength to the puregold.
Reasons for adding:
Why Silver:
As the proportion of silver increases, gold changes in colour from yellow to greenish-yellow, to white.
Why Copper:
As copper content increases, the gold becomes redder in appearance.
Why Nickel:
Nickel has the effect of whitening gold.
Why Zinc:
Zinc is considered a decolorizer, and is used to convert some red golds (copper alloys) into a more yellowish tone by substitution of zinc for some of the copper and silver.
How to Calculate Carats of purity in Gold
Carat is the measure of purity of gold. In the carat system pure gold is expressed as 24 Carat fine (24K). Pure gold in commercial practice is 99.5 to fine, however, it is normally considered as 100%.
The most popular jewelry golds in the United States are:
- 24K (99.95% gold)
- 18K (75% gold)
- 14K (58.33% gold)
- 10K (41.67% gold)
How to Calculate Carats in Gold?
Carat = 24 X (G/M)
| where | G | = | Mass of gold in the material |
| M | = | Mass of the material |
let us take an example, 300 gm of gold chain contains only 200 gm of gold material and the remaining 50gm is other materials (Silver, Copper, Nickel, Zinc)
| Carat (K) | = | 24 | X | (200/300) |
| = | 18 | |||
| = | 18 K |
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