Summers in phoenix arizona are hot (125 f is not uncommon), and dry. if you hop into an outdoor swimming pool on a summer day in phoenix, you will find that the water is too warm to be very refreshing. however, when you get out of the pool and let the sun dry you off, you find that you are quite cold for a few minutes.

Explanation:

when we get out of the water we feel quite cold due to the latent heat of evaporation of water.

Water at our body gets converted into gas and leaves behind the cooling effect which makes us feel cold.

While when we are inside the pool we are in constant touch of water, therefore, we get the warmth of the water and it becomes difficult to bear it.

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)

-first use of geothermal energy occurred more than 10,000 years ago in north america by american paleo-indians

-the first industrial use of geothermal energy began near pisa, italy in late 18th century

-in 1904, italian scientist piero ginori conti invented the first geothermal electric power plant in which steam was used to generate the power

-with the above experiment, the first geothermal plant in usa started in 1922 with a capacity of 250 kilowatts

-however, in 1946 first ground-source geothermal heat pump installed at commonwealth building in portland, oregon

-during the 1960’s, pacific gas and electric began operation of first large scale geothermal power plant in san francisco, producing 11 megawatts

-in 1973, when oil crisis began many countries began looking for renewable energy sources and by 1980’s geothermal heat pumps (ghp) started gaining popularity in order to reduce heating and cooling costs

-as effect of climate change started showing results, governments of various countries joined hands to fight against it, for which kyoto protocol was signed in japan in 1997, laid out emission targets for rich countries and required that they transfer funds and technology to developing countries, 184 countries have ratified it

hope this