WavelengthIn physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, troughs, or zero crossings. Wavelength is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The inverse of the wavelength is called the spatial frequency.
Trade barrierTrade barriers are government-induced restrictions on international trade. According to the theory of comparative advantage, trade barriers are detrimental to the world economy and decrease overall economic efficiency. Most trade barriers work on the same principle: the imposition of some sort of cost (money, time, bureaucracy, quota) on trade that raises the price or availability of the traded products. If two or more nations repeatedly use trade barriers against each other, then a trade war results.
