Please help with these three questions.

The electrons in the diagram have slowed to a stop and have just started their return to the left plate. What is the best estimate of the energy these electrons had when they were emitted?
a) 0.5 eV
b) 0.9 eV
c) 1.1 eV
d) 2.0 eV

What is the effect of doubling the intensity of light on whether electrons will be emitted from a metal?
a) The more intense light is more likely to cause electrons to be emitted than the weaker light.
b) The more intense light will cause electrons to be emitted with faster velocities than the weaker light.
c) The less intense light must shine for a longer time to cause electrons to be emitted.
d) Light intensity has no effect on whether electrons are emitted or not.

A physicist is asked to analyze two mystery metals. Each metal is struck by light with three different wavelengths: 300 nm, 400 nm, and 500 nm. In each case, the physicist adjusts the voltage gradient to determine the energies of the emitted electrons. The results are shown in the chart below. What are the values of X and Y?
a) X=1.9eV,Y=0.2eV
b) X=2.1eV,Y cannot be determined
c) X=2.1eV,Y=0.2eV
d) X=1.9eV,Y cannot be determined