(i) Give reason for using dark coloured clothes in winter and bottom of utensils used for cooking food being black.
(ii) Draw a table to compare the Kelvin, Celsius and Fahrenheit scales of temperature (steam point, ice point, absolute zero).
(i) Give reason for using dark coloured clothes in winter and bottom of utensils used for cooking food being black.
(ii) Draw a table to compare the Kelvin, Celsius and Fahrenheit scales of temperature (steam point, ice point, absolute zero).
(ii) Draw a table to compare the Kelvin, Celsius and Fahrenheit scales of temperature (steam point, ice point, absolute zero).
Text Solution
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(a) Black bodies absorb and emit radiant energy better than bodies of lighter colours. During winter, we use dark
coloured clothes which absorb heat from the sun and keep our body warm. However we wear white or light coloured clothes in summer so that they absorb the least heat from the sun. The bottoms of the utensils for cooking food are blackened so that they absorb maximum heat from the fire and give it to the vegetables to be cooked.
(b) Steam point 373.15 K 100.00°C 212.00°F
Ice point 273.15 K 0.00°C 32.00°F
Absolute zero 0.00 K –273.15°C –459.69°F
coloured clothes which absorb heat from the sun and keep our body warm. However we wear white or light coloured clothes in summer so that they absorb the least heat from the sun. The bottoms of the utensils for cooking food are blackened so that they absorb maximum heat from the fire and give it to the vegetables to be cooked.
(b) Steam point 373.15 K 100.00°C 212.00°F
Ice point 273.15 K 0.00°C 32.00°F
Absolute zero 0.00 K –273.15°C –459.69°F
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