The magnetic field is decreasing. what is the induced electric field?

The induced electric field will be constant i.e zero

Explanation:

Magnetic field is a region of space where magnetic force can be felt while electric field is a region of space where electric force can be felt. This two field are related because they tend to talk about force of attraction and repulsion. Example is running a current through a thin wire near a magnet, the direction of one of the field will determine the direction of the other.

According to the question, if the magnetic field is decreasing, the electric field will adjust by traveling in opposite direction to the magnetic field just to make the field constant.