"why does the temperature remain constant during a phase change the heat added

Which of the following is an example of motion in two dimensions?

If angle "a" is 25°, angle "b" is: a) equal to angle c b) less than angle c c) greater than angle c

The electric field between square plates of a parallel-plate capacitor has magnitude e. the potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. the magnitude of the electric field between the plates is now equal to a)e b)e/4 c)e/2 d)4e e)2e