Yes, an electric field can be created without any physical source through the phenomenon of induction. When a charged object is brought near a neutral object, it can create an electric field in the neutral object without making physical contact.
An electric field can be stronger than the field generated by a single charge by using multiple charges. The electric field created by multiple charges can add up and create a stronger field than that of a single charge. This is known as the superposition principle.
No, electric field strength is always positive. It represents the force experienced by a positive charge in the field. However, the direction of the field can be negative, indicating that the force experienced by a positive charge would be in the opposite direction.
Yes, an electric field can exist in a vacuum. In fact, light is an example of an electric field in a vacuum. The electric and magnetic fields oscillate perpendicular to each other and propagate through the vacuum.
Electric fields can be used for levitation by creating a strong electric field between two objects with opposite charges. The force of the electric field can counteract the force of gravity, allowing the objects to float in midair. This principle is utilized in technologies such as maglev trains and levitating displays.