Question

directions: select all the correct answers. which of the following are true about electricity and magnetism? energy cannot be transferred by an electric current. a magnetic force can attract a metal object only if the object is touching the magnet. a magnetic force can be produced by an electric current. an electric current can be produced by a changing magnetic force.

Explanation:

1. Electric current can transfer energy, for example in electrical devices that convert electrical energy to other forms. So the statement "Energy cannot be transferred by an electric current" is false.
2. A magnetic force can attract a metal object without physical contact, as seen with magnets attracting iron - nails from a distance. So the statement "A magnetic force can attract a metal object only if the object is touching the magnet" is false.
3. According to electromagnetism, an electric current can produce a magnetic field, which means a magnetic force can be produced by an electric current. This is true.
4. Faraday's law of electromagnetic induction states that an electric current can be produced by a changing magnetic force (or a changing magnetic flux). This is true.

Answer:

C. A magnetic force can be produced by an electric current.
D. An electric current can be produced by a changing magnetic force.