What is the difference between electric field and electrostatic field?

Semantically? An electric field does not have to be static while in electrostatics it's generally assumed that the electric field does not change or only changes so slowly that its rate of change doesn't matter. That's very different in electrodynamics where electric and magnetic field changes are always coupled.

The main difference is that Electrostatic field is because of a stationary charge. And Induced field is because of a changing magneticfield. Since magnetic field and electric field are the same thing in different frames of reference.

The purpose of a lab is to do your "expirements" the importance of the topic is so you can now what the story is about and the last one is because no one is me with my question ( what is 3 over 4 x - 9 = 27 maybe you can )

  concave means having an outline or surface that curves inward like the interior of a circle or sphere. so the mirror curves inward.