Homework No. 6 on Electromagnetism (Pg 1 of 2) Due date: February 21, 2017 Name:_______________ Please, answer all 10 questions by selecting only one letter for each question. The magnetic field forces exerted between two opposing magnets use the path of highest resistance.----------------------------------------------------------------------------------------------------T---F The magnetic field is created by an electric current (electromagnet) or the by an already permanently magnetized material spinning motion of electrons (permanent). ----------------------------------------T---F Around a current-carrying wire the magnetic field is made stronger by coiling the wire.-----------T---F An electric current always creates a magnetic field.----------------------------------------------------------T---F Magnetic forces are forces that arise from the movement of molecules.-------------------------------T---F Permanent magnets are made of soft ferromagnetic material.--------------------------------------------T---F 7. Magnetic permeability, μ is (a) magnetization that a material obtains in response to an applied magnetic field or (b) material’s ability to support the formation of a magnetic field or ( c) both------------------------------- Answer: Permanent magnets are used in: (a) speakers; (b) electric motors; (c ) compasses; (d) all of the above; ------- Answer: A compass cannot follow magnetic field lines because it needs to point toward the North Pole-- T—F 10. Electromagnets are used: (a) to lift heavy objects; (b) to separate metal from junk; (c) in electric motors (d) all of the above; Answer:

Homework No. 6 on Electromagnetism (Pg 2 of 2) Due date: February 21, 2017 Name:______________________ Please, answer all 5 questions by selecting only one letter for each question. An electron passes through a magnetic field without being deflected. What do you conclude about orientation between the magnetic field and the velocity of the electron, assuming there are no other forces acting on electron? Answer:___ A charge of 0.05 C moves vertically in a field of 0.0 T that is oriented horizontally. What speed must the charge have such that the force acting on it is 10 N? Answer:___ A long, straight current-carrying wire is oriented vertically. On its east side, the field it creates points south. What is the direction of the current? a) Up or b) down. Answer:___ The main source of magnetism in magnetic materials is from a) electron orbit, b) electron spin, c) magnetic poles, or d) nuclear properties. Answer:___ How can you destroy or reduce the magnetic field or permanent magnet? Answer:___