The equation for electric field in terms of a changing magnetic field is given by E = -∆B/∆t, where E is the electric field, B is the magnetic field, and ∆t is the change in time.
The direction of the electric field from a changing magnetic field can be determined using the right-hand rule. If the fingers of your right hand point in the direction of the changing magnetic field, then your thumb will point in the direction of the electric field.
No, according to Faraday's law of induction, a changing magnetic field will always produce an electric field. Therefore, an electric field cannot exist without a changing magnetic field.
The magnitude of the electric field is directly proportional to the rate of change of the magnetic field. This means that a larger change in the magnetic field will result in a stronger electric field.
The equation for electric field given a changing magnetic field is a fundamental part of Maxwell's equations, which describe the behavior of electromagnetic waves. Electromagnetic waves are created by oscillating electric and magnetic fields, and the equation for electric field is essential in understanding their behavior.