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प्रश्न
Explain the following
Fishes survive in ponds even when the atmospheric temperature is well below 0°C.
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उत्तर
The anomalous expansion of water helps preserve aquatic life during very cold weather. When temperature falls, the top layer of water in a pond contracts becomes denser and sinks to the bottom. A circulation is thus set up until water in the pond reaches its maximum density at 4°C. If the temperature falls further, then the top layer expands and remains on the top till it freezes. Thus, even though the upper layer are frozen, the water near the bottom is at 4°C and the fishes can survive in it easily.
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संबंधित प्रश्न
Consider the situation of the previous problem. Assume that the temperature of the water at the bottom of the lake remains constant at 4°C as the ice forms on the surface (the heat required to maintain the temperature of the bottom layer may come from the bed of the lake). The depth of the lake is 1.0 m. Show that the thickness of the ice formed attains a steady state maximum value. Find this value. The thermal conductivity of water = 0.50 W m−1°C−1. Take other relevant data from the previous problem.
How do fishes survive in frozen lakes?
Why does a thick glass tumbler crack when very hot water is poured in it?
_______ apparatus is used to study the anomalous behaviour of water.
In cold regions, in winter the pipes for water supply break.
Write a short note.
Anomalous behaviour of water
Observe the given picture and answer the following questions.
- Which property do you understand in this picture?
- What is the temperature of the water at the surface?
- What is the temperature below the layer of ice on the surface?
