Sound that is perceptible by humans has frequencies from about 20 Hz to 20,000 Hz. In air at standard temperature and pressure, the corresponding wavelengths of sound waves range from 17 m to 17 mm. Sometimes speed and direction are combined as a velocity vector; wave number and direction are combined as a wave vector.
Price of a Stamp. The current price of a first class stamp is 47 cents. A domestic first class letter (1 oz.) is 47 cents. The price of each additional ounce is 21 cents. It will cost you 34 cents to send a domestic postcard.
How Much Does a Stamp Cost? Typical costs: The cost to mail a first class letter is 46 cents for up to one ounce, and each additional ounce adds 20 cents. Large envelopes (flats) that are rectangular and not too rigid or thick are 90 cents for up to one ounce (and 20 cents for each additional ounce).