An oil drop is observed to remain motionless between the plates of the chamber for a certain value of the upward electric field in the oil drop experiment. Which statement about the electric field is true?

The force due to the electric field is greater than the weight of the oil drop.

The force due to the electric field is less than the weight of the oil drop.

The force due to the electric field is exactly equal to the weight of the oil drop.

The force due to the electric field fluctuates.

Air enters a gas turbine with two stages of compression and two stages of expansion at 100 kpa and 17°c. this system uses a regenerator as well as reheating and intercooling – the intercooler returns the air to the inlet temperature. the pressure ratio across each compressor is 4 ; 300 kj/kg of heat are added to the air in each combustion chamber; and the regenerator operates perfectly while increasing the temperature of the cold air by 20°c. determine the system’s thermal efficiency. assume isentropic operations for all compressor and the turbine stages and use constant specific heats at room temperature. (0.378)