A motor car, with its glass totally closed, is parked directly under the sun. The inside temperature of the car rises very high. Explain why?

On a hot day, a car is left in sunlight with all the windows closed. After sometimes, it is found that air inside the car is considerably warmer than the air outside. Explain why?

A block is kept in a room which is at 20^(@)C . To raise the temperature of the block, heat is given to it at a constant rate of 600 watt (using an electric heater). The temperature of the block rises with time as shown in the graph. The slope of the graph at time t = 0 is 3^(@)C s^(-1) . Once the temperature rises to 60^(@)C , the heater is switched off and another heater is switched on to maintain the temperature of the block at 60^(@)C . This new heater supplies heat at a constant rate of 100 watt. Assume that heat capacity of the block remains constant for the range of temperature involved. (a) Explain why the slope of the given graph is decreasing with time. (b) Calculate the heat capacity of the block. (c) If the 100 W heater is also switched off, what will be initial rate of cooling of the block? (d) Assuming that rate of heat loss by the block to the surrounding is proportional to difference in its temperature with surrounding, calculate the heat radiated per second by the block when it was at 30^(@)C .

Three very large plates of same area are kept parallel and close to each other. They are considered as ideal black surface and have very high thermal conductivity The first and thired plates are maintained at temperatures 2T and 3T respectively Find the temperature of the middle (i.e second) plate under steady state .

Calculate the rms speed of He and N_(2) molecules in the atmosphere at 300 K. Explain why our atmosphere has only a small amount of helium though it has large nitrogen content. The sun has temperature close to 6000 K. How can you explain the existence of He in the Sun.

In both alkyl halides, The halogen atom is attached directly to the carbon atoms. They are expected to exhibit similar reactivity. However,aryl halides are comparatively little reactive, particularly towards nucleophilic substitution reactions. For example, hydrolysis of ethyl chloride takes place by simple boiling with aqueous KOH. On the other hand, the alkaline hydrolysis of chlorobenzene needs a very high temperature (623 K) as well as very high pressure Benzene reacts with Cl_(2) in the presence of FeCl_(3) (and absence of sun hight) to form