760 mm Hg
Atmospheric pressure: The atmospheric air exerts a normal pressure upon all surfaces with which it is in contact and it is known as atmospheric pressure. Atmospheric pressure is also known as barometric pressure. The atmospheric pressure at sea level (above absolute zero) is called standard atmospheric pressure and its value is given as follows:
Standard atmospheric pressure = 101.3 kN/m2 or kPa (1 kN/m2 = 1 kPa)
= 10.3 m of water
= 760 mm of Hg
Atmospheric pressure = Absolute pressure - Gauge pressure
conservation of energy
First law of thermodynamics: First law of thermodynamics states that, Heat and mechanical work are mutually convertible. According to this law, a definite amount of mechanical work is needed to produce a definite amount of heat and vice versa. The first law of thermodynamics is the law of conservation of energy.
First law of thermodynamics also states that energy can neither be created nor destroyed, through it can be transformed from one form to another. According to this law, the energy due to heat supplied must be balanced by external workdone plus the gain in internal energy due to rise in temperature.