Geography Write short notes on given topics.

(ii) The vertical distance between a crest and the following trough is called the amplitude of the wave whereas the distance between two successive crests or troughs is called wave length.

(iii) The wave length, its amplitude & its velocity depend on the velocity of the wind.

• The sea water gets pushed by the wind and ripples are generated on the water surface. These are called waves.
• The sea water moves up & down or slightly forward & backward due to the waves.
• The waves bring the energy contained in them to the coast.
• Large & small waves are formed continuously at the surface of the sea.
• Generation of waves is a natural & regularly occurring phenomenon.

(ii) This position occurs on the first and third quarter of each month. On both these days the forces of both the sun & the moon operate at right angles on the earth.

(iii) At the places where the sun causes high tide, the gravitational pull of the moon which is at right angles also acts on the water.

(iv) Due to such conditions the water level rise is less than usual at the time of high tide. Similarly, fall in water level is less than usual at the time of low tide.

(v) Such tides are called neap tides.

(ii) Hence, the tide on these days is much higher than the average high tide.

(iii) This is known as spring tide.