The red wavelengths of light are the longer wavelengths and the violet wavelengths of light are the shorter wavelengths. Between red and violet, there is a continuous range or spectrum of wavelengths.
The USPS also includes that a large postcard is 49 cents to mail. The maximum size for this postcard is 11 1/2 inches long, 6 1/8 inches high and 1/4 inch thick. This is the same rate to mail a First Class 1 ounce letter domestically. The rates for postage increased as of January 2014.
That means that the cost of a stamp to mail a standard letter will decrease from 49 cents to 47 cents this Sunday. The price of sending a postcard will also drop by a penny, to 34 cents, while international mail will go down by a nickel, to $1.15 per letter instead of the current $1.20.