A diode vacuum tube consists of a cathode and an anode spaced 5 rom apart. If 300 volts are placed across the electrodes. (a) What is the velocity of the electron midway between the electrodes, and at the instant of striking the plate, if the electrons are emitted by the cathode with zero velocity? (b) If the plate current is 20 rnA, what is the average force exerted on the anode?