From a new Moon, when the Moon is situated in orbit between the Earth and the Sun with its dark side in shadow facing towards us, the amount of lunar surface visible from the Earth increases through waxing crescent, first quarter and waxing gibbous phases until it becomes full.
The new moon is the phase that is invisible to us here on Earth because the moon is between the earth and the sun, and its illuminated side is facing away from us. A solar eclipse occurs when the moon moves in front of the sun, blocking it from our view on Earth.
<em>The conversion of water of 20.0 °C to the ice of –20.0 °C will comprise of three steps:</em>
cooling of water to 0 °C
formation of ice at 0 °C from the water of 0 °C
further cooling of ice of 0 °C to -20 °C
Latent heat of fusion of ice,
specific heat of water,
specific heat of ice,
Now, total heat lost in the process:
= change in temperature of ice and water respectively.
is the total heat extracted during the process.
So, 556464 joule is the minimum electrical energy <em>(by the law of energy conservation under no loss condition)</em> required by refrigerator to carry out this process if it operates between the reservoirs at temperatures of 20.0 °C and -20.0 °C, because for a <em>refrigerator to work in a continuous cycle it is impossible to transfer heat from a low temperature reservoir to a high temperature reservoir without consuming energy in the form of work.</em> Here 556464 joule is the heat of the system to be eliminated.