Magnetic fields and electromagnets 1 Electric Currents Magnetism

Magnetic fields and electromagnets 1

Electric Currents & Magnetism Since moving charges create magnetic fields, an electric current creates a magnetic field. A coil of wire can concentrate the magnetic field and create an electromagnet.

Magnetic Forces on Charges A static electric charge does not “feel” a magnetic field. No magnetic force is exerted on it. If an electric charge moves, it generates its own magnetic field, which interacts with the original magnetic field, so: A magnetic field exerts a force on a moving electric charge.

4 Right Hand Rule Thursday, January 27, 2022

5 Thursday, January 27, 2022 If: F = Magnetic force (in Newtons) q = amount of charge (in Coulombs) v = Velocity of the charge B = Strength of the magnetic field (in Tesla) = Angle between B and v Then: F = qv. Bsin The maximum magnetic force is achieved when the charges are moving perpendicular to the field. = 90˚

6 Thursday, January 27, 2022 Question 1 A particle of charge q = 2. 3 x 10 -6 C moves with velocity v = 1. 6 x 103 m/s in a magnetic field of 3 T. Find the magnitude of the force on the charged particle.

7 Thursday, January 27, 2022 Question 1 A particle of charge q = 2. 3 x 10 -6 C moves with velocity v = 1. 6 x 103 m/s in a magnetic field of 3 T. Find the magnitude of the force on the charged particle. F = qv. Bsin Assume maximum force generated. Sin(90) = 1 F = (2. 3 x 10 -6 C)x(1. 6 x 103 m/s)x(3 T)x(1) F = 0. 011 N

Magnetic Forces on Electric Currents If a magnetic field exerts a force on a moving charge, a magnetic field must exert a force on a current-carrying wire.

9 Thursday, January 27, 2022