Heat and Thermodynamics part-(1)

Whether a given cloud will heat or cool the surface depend on several factors, including the cloud's altitude, its size, and the make-up of the particles that form the cloud. Low, thick clouds primarily reflect solar radiation and cool the surface of the Earth. While high, thin clouds primarily transmit incoming solar radiation; at the same time, they trap some of the outgoing infrared radiation emitted by the Earth and radiate it back downward, thereby warming the surface of the Earth. Hence, both of the given statements are incorrect

The specific heat capacity is the property of the substance which determines the change in the temperature of the substance (undergoing no phase change) when a given quantity of heat is absorbed (or rejected) by it. It is defined as the amount of heat per unit mass absorbed or rejected by the substance to change its temperature by one unit. Water has the highest specific heat capacity compared to other substances. The specific heat of water is much greater than that of land surface. Owing to its high specific heat capacity, the water of ocean warms up much more slowly than the land during summer and consequently wind from the sea has a cooling effect. On the other hand, the ocean slowly cools in winter keeping the air warm .That is the reason why the temperature contrast between continent and ocean is greater during summer than in the winter hence both of the statement 1 and the statement 2 is the correct explanation for the statement 1

It is well known that the even after harvesting of the fruit the process of respiration continues and brings about the ripening change in colour softening of flesh increase in sugar content and development of flavour .These changes occur more rapidly at higher temperature this means that the lower the temperature of storage the longer would be the storage life of the fruit. In cold chamber the rate of respiration of fruits is decreased.

Woollen clothes keep us warm in winter. It is just because woollen clothes have fibres and between those fibres, air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Thus statement (A) is correct but reason (R) is false.

Humidity is the percentage of water vapour present in air. As the humidity increases, the percentage of water vapour in air increase and this decreases the density of air. This results in the increase of velocity of sound. So increase in the humidity of air increases the velocity of sound in air. Thus, statement (c) is not correct.

If the door of a refrigerator kept open in a room, the temperature will start to rise inside the refrigerator. The thermostat will kick in and try to cool it back down. This means the motor is running, which means heat is being added to the room resulting warmer room.

If the door of a refrigerator kept open in a room, the temperature will start to rise inside the refrigerator. The thermostat will kick in and try to cool it back down. This means the motor is running, which means heat is being added to the room resulting warmer room.

The kelvin scale has no negative values.The kelvin scale is the best representation of average kinetic molecular energy when a substance has a temperature of 0k (-273.15 degree celsius) it is at absolute zero and has no kinetic energy all because its particles stop moving .

The formula  to convert Fahrenheit (°F) to celsius (°C) is

C=(F-32)*5/9

since the temperature in °F=200°F

∴ C=(200-32)*5/9

=168*5/9=840/9=93.3

so the value of 200°F is 93.3°C  in celsius scale

The relation between Centigrade (C) and Fahrenheit (F) is -
⇒
∴ average temperature in Centigrade is ¯C and Fahrenheit is ¯F
∴ relationship between ¯C and ¯F
¯F=9/5¯C+32