Your friend is asked to differentiate between evaporation and boiling. What questions could you ask to make him to know the differences between evaporation and boiling? `(AS_2)`

When a situation demands our immediate action, it takes some time before we really respond. Reaction time is the time a person takes to observe, think and act. For example, if a person is driving and suddenly a boy appears on the road, then the time elapsed before he slams the brakes of the car is the reaction time. Reaction time depends on complexity of the situation and on an individual. You can measure your reaction time by a simple experiment. Take a ruler and ask your friend to drop it vertically through the gap between your thumb and forefinger . After you catch it, find the distance d travelled by the ruler. In a particular case, d was found to be 21.0 cm. Estimate reaction time.

Take 2kg of ice is at - 5^@ C. Supply heat is continuously to ice. Till it starts boiling. Note the temperature every minute. Draw a graph between temperature and time using the values you get. What do you understand from the graph. Write the conclusions. ( You know that ice melts at 0^@ c and boils at l00^@C

Guess my number : Your frient chooses an integer between 0 and 100. You have to find out that number by asking questions, but your friend can answer only in 'yes' or 'no'. What strategy would you use?

Surafce tension is exhibited by liquids due to force of attraction between the molecules of the liquid .The surface tension decreases with increases in temperature and vanishes at boiling point Given that the latent heat of vaporization for water L_(v)=540(kcal)/(kg) the mechanical equivalent of heat J=4.2(J)/(cal) density of water rho_(w)=10^(3)kgl^(-1) ,Avogadro'sno. N_(A)=6.0xx10^(26)k " mole"^(-1) . Molecular weight of water M_(A)=10kg , for 1k mole . (a) Estimate the energy required for one molecule of water to evaporated. (b) Show that the inter molecular distance for water is d=((M_(A))/(N_(A))xx(1)/(rho_(w)))^((1)/(3)) and find its value. (c ) 1 g of water in the vapour state at 1 atm occupies 1601cm^(3) , estimate the intermolecular distance at boiling point in the vapour state. (d) During vaporisation a molecule overcomes a force F, assumed constant to go from an inter molecular distance d to d .Estimate the value of F. (e ) Caculate (F)/(d) , which is a measure of the surface tension.

Four friends went to a picnic. The weather was pleasant. They played various games and then had snacks. Suddenly, Raju, one of them, observed seven colours in the sky. He said to others, "wow what a rainbow"! Ram, one of them, asked him "What is a rainbow?" Raju then explained to all about its formation. After that everyone in the group thanked Raju for the knowledge, he had given to them. What moral value do you learn from Raju ?

In a beautiful valley, there was a village. When trains passed from the village, the whistle and the sound of train, mixed with the sound of waterfall, seemed to be very pleasant to everyone. Hence, children of that village used to play near the railway track. Once on a very light foggy day, a group of children found that a fish plate was missing from the track. As such, all the villagers were worried. Prashant, one of the children, suddenly put his ear to the line and tried to know whether a train is coming or not. He knew a train is coming. He asked his friends to inform the railway cabin crew and he himself put off his red shirt and started running towards the train, waving his red shirt. The driver and cabin man got the alert signal in time and thus a major accident was averted. What moral values do you learn from Prashant ?