A10.0 nc point charge and a 20.0 nc point charge are 15.0 cm apart on the x axis. a) what is the electric potential at the point on the x axis where the electric field is zero? b) what is the magnitude of the electric field at the point on the x-axis, between the charges, where the electric potential is zero? c) what is the direction of the electric field at the point on the x-axis, between the charges, where the electric potential is zero?

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

If 21.2 kcals of energy is released by this reaction, how many kj does the reaction release? (1 cal 4.184 j)

Idon’t quite understand this problem