18. Magnetism produced by an electric current is called a. electromagnetism b. ferromagnetic c. electromagnet d. magnetic field 20. What is it called when the net forces equal 0 N? a. unbalanced forces b. push forces c. pull forces d. balanced forces 22. Mike exerts a 35 N force on a box, and Fin exerts a 125 N force in the same direction. What net force both of them do exert on a box? a. 120 N b. 160 N c. 90 N d. 70 N

55.  A magnet does not exert a force on   A. a magnetized iron bar     B. a moving positron   C. a stationary electric charge   D. a moving alpha particle   E. an un-magnetized iron bar

8. A wire carrying a 36.0–A current passes between the poles of a strong magnet that is perpendicular to its field and experiences a 2.15–N force on the 4.40 cm of wire in the field. What is the average field strength?   This is not and will not be graded

Identify the object that would not experience force due to a magnet? Select one: a. Water b. Nail c. Screw d. scissor

*42. A bar magnet is divided into two pieces. Which of the following statements is true about the force between the broken pieces if they face each other with a small separation? Group of answer choices There is an electric attractive force between the broken pieces. There is an electric repulsive force between the broken pieces. There is a magnetic attractive force between the broken pieces. There is a magnetic repulsive force between the broken pieces.

It is the combination of the magnetic and electric force on a point charge due to electromagnetic fields. It is used in electromagnetism and is also known as the electromagnetic force. What force is this?        A. Lorentz force B. Frictional force C. Gravitational force D. Gaussian force

WHICH OF THE FOLLOWING DIFFER AN ELECTROMAGNETS FROM A MAGNETS? A. MAGNETS CAN BE TURNED ON OR OFF B. YOU CAN TURN AN ELECTROMAGNETIC ON AND OFF C. MAGNETS ARE MORE POWERFUL D. MAGNETS HAVE BOTH NORTH AND SOUTH POLE

Describe the origins of the magnetic field of the Earth. Describe what is meant by magnetic field strength and state its unit of measurement in SI units. Select one or more: a. Magnetic field strength is measured in amperes per meter squared. b. О с. d. The magnetic field strength B is the value of the current in the loop per unit area. The magnetic field of the earth is caused by electric currents inside the molten iron core of the Earth. The magnetic field strength B is defined as the force acting per unit current in a wire of unit length when the wire is perpendicular to the magnetic field lines. e. The magnetic field of the earth is caused by Earth's rotation around the Sun. ☐ f. Magnetic field strength is measured in Tesla.

At null points, the resultant magnetic field is: Oa.maximum O b. none of these OC. zero O d. equal to earth's magnetic field