Explanation
For cooking utensils, low specific heat is preferred for it’s material as it should need less heat to raise it’s temperature and it should have high conductivity, because, it should transfer heat quickly.
It is the property of material.
Because steady state has been reached.
When a piece of glass is heated, due to low thermal conductivity it does not conduct heat fast. hence unequal expansion of it’s layers crack the glass.
In winter, the temperature of surrounding is low compared to the body temperature (37.40 C). Since, woolen clothes are bad conductors of heat, so they keep the body warm.
Mud is bad conductor of heat. So, it prevents the flow of heat between surroundings and inside.
Heat passes quickly from the body into the metal which leads to a cold feeling.
Heat energy always flow from higher temperature to lower temperature. Hence, temperature difference w.r.t. length (temperature gradient) is required to flow heat from one part of a solid to other part.
When the temperature of an object is equal to that of human body, no heat is transferred from the object to body and vice versa, Therefore, block of wood and block of metal feel equally cold and hot if they have same temperature as human body.
Temperature of water just below the lower surface of ice layer is 00C.
A lake cools from the surface on bottom. Above 4°C, the cooled water at the surface flows to the bottom because of it’s greater density. But when the surface temperature drops below 4°C (here it is 2°C), the water near the surface is less dense than the warmer water below. Hence the downward flow ceases, the water at the bottom remains at 4°C until nearly the entire lake, is frozen.
Thermal resistance of Cu is lesser than the thermal resistance of steel. hence, only in option (a) thermal resistance is minimum so heat current is maximum.
Density of hot air is lesser than the density of cold air so hot air rises up.
Convection is nor possible in weightlessness. So, the liquid will be heated through conduction.
Because of uneven surfaces of mountains, most of it’s parts remain under shadow. So, most of the mountains, land is not heated up by sun rays. Besides this, sun rays fall slanting on the mountains and are spread over a larger area. So, the heat received by the mountains Lop per unit area is less and they are less heated compared to planes (Foot).
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