Electricity and Magnetism Answers

A proton travels in a circular path with a radius of 4.10 mm in a magnetic field of strength 1.90 T. a) Calculate the speed of the proton. b) Determine the time required for it to make one–half of a revolution. 

. Show that a uniform electric field cannot exist in the presence of a time-dependent magnetic field.

Show that a time-dependent magnetic field cannot exist without an electric field.

 A long straight wire carries a current. The strength of the magnetic field, due to the wire, 10.0 cm from the axis of the wire is 20T . Determine the current in the wire. 

 A conducting circular loop of radius r carries a constant current i. It is placed in a uniform magnetic field B such that B is perpendicular to the plane of the loop. Calculate the magnetic force acting on the loop.

An electric dipole, consisting of magnitude 2.80 nC separated by 4.60  m, is in a uniform electric field of magnitude 3400 N/C. (a) Calculate the magnitude of the electric dipole moment. (b) Calculate the difference in potential energy corresponding to dipole orientations parallel to and antiparallel to the electric field.

An electric dipole with dipole moment of magnitude 3.75 x 28 10 Cm is in an electric field of magnitude 9500 N/C. Compute the magnitude of the torque on the dipole when the dipole moment is (a) perpendicular to the electric field, (b) parallel to the electric field and (c) antiparallel to the electric field.

A straight wire, 0.05 m long, is placed in a uniform magnetic field of magnetic induction 0.04 T. The wire carries a current of 7.5 A, and makes an angle of 60° with the direction of the magnetic field. The arrow on the wire shows the direction of the electron current in the wire. (a) Calculate the magnitude of the force exerted on the wire. (b) Draw a sketch of the wire in the magnetic field and show the direction of the force. (c) Describe the conditions for this force to be a maximum. 

Suppose you have two small "point" objects separated by a distance of 1 cm. Each object has a diameter of 10 −3 cm. One object has an excess of 3 × 10 10 electrons and the other has an excess of 2 × 10 10electrons on it. What is the electrostatic force that they exert on each other?

1)Two oppositely charged horizontal plates are separated by a distance d =1 cm and each has a length L =3 cm, see Fig. below. The electric field between the plates is uniform and has a magnitude E =102 N/m. An electron is projected between the plates with a horizontal initial speed of 𝑣0=106 𝑚/𝑠 as shown. Assuming this experiment is conducted in a vacuum, where will the electron strike the upper plate? Repeat when a proton replaces the electron.