How much energy is required to move an electron through a potential difference of 12 V?

1) 1.9 x 10^- 18 )
2) 7.5 x 10^- 18 )
3) 1.3 x 10^-20)
4) 7.5 x 10^18 J

Water is siphoned from a large tank and discharges into the atmosphere through a 50-mm diameter tube. the end of the tube is b = 2.1 m below the tank bottom which is a = 7.4 m deep, and viscous effects are negligible. determine the maximum height h over which the water can be siphoned without cavitation occurring. atmospheric pressure is 101.4 kpa, and the water vapor pressure is 1.79 kpa (absolute)