Choose all of the statements that are true about electromagnets: 1. electromagnets are permanent and always have a magnetic field around them. 2. electromagnets can be made stronger by adding more coils to the solenoid. 3. electromagnets can be made stronger by increasing the strength of the electrical source. 4. none of the above.

Place several e-field sensors at a few points on different equipotential lines, and look at the relationship between the electric field and the equipotential lines. which statement is true? 1-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of higher voltages. 2-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of lower voltages. 3-at any point, the electric field is parallel to the equipotential line at that point.