Exam 27: Magnetic Field and Magnetic Forces

A rigid circular loop has a radius of 0.20 m and is in the xy-plane.A clockwise current I is carried by the loop,as shown.The magnitude of the magnetic moment of the loop is A uniform external magnetic field,B = 0.20 T in the positive x-direction,is present.An external torque changes the orientation of the loop from one of lowest potential energy to one of highest potential energy.The work done by this external torque is closest to

An electron traveling toward the north with speed 4.0 × 10⁵ m/s enters a region where the Earth's magnetic field has the magnitude 5.0 × 10^-5 T and is directed downward at 45° below horizontal.What is the magnitude of the force that the Earth's magnetic field exerts on the electron? (e = 1.60 × 10^-19C

A proton starting from rest travels through a potential of 1.0 kV and then moves into a uniform 0.040-T magnetic field.What is the radius of the proton's resulting orbit? ,

Ions having equal charges but masses of M and 2M are accelerated through the same potential difference and then enter a uniform magnetic field perpendicular to their path.If the heavier ions follow a circular arc of radius R,what is the radius of the arc followed by the lighter?

A beam of electrons is accelerated through a potential difference of 10 kV before entering a region having uniform electric and magnetic fields that are perpendicular to each other and perpendicular to the direction in which the electron is moving.If the magnetic field in this region has a value of 0.010 T,what magnitude of the electric field is required if the particles are to be undeflected as they pass through the region?

A round loop of diameter 12 cm,carrying a current of 0.40 A,is placed inside a magnetic field = 0.20 T + 0.40 T .The normal to the loop is parallel to the unit vector What is the potential energy of the loop?

A straight 15.0-g wire that is 2.00 m long carries a current of 8.00 A.This wire is aligned horizontally along the west-east direction with the current going from west to east.You want to support the wire against gravity using the weakest possible uniform external magnetic field. (a)Which way should the magnetic field point? (b)What is the magnitude of the weakest possible magnetic field you could use?

An electron moving in the direction of the +x-axis enters a magnetic field.If the electron experiences a magnetic deflection in the -y direction,the direction of the magnetic field in this region points in the direction of the

An L-shaped metal machine part is made of two equal-length segments that are perpendicular to each other and carry a 4.50-A current as shown in the figure.This part has a total mass of 3.80 kg and a total length of 3.00 m,and it is in an external 1.20-T magnetic field that is oriented perpendicular to the plane of the part,as shown.What is the magnitude of the NET magnetic force that the field exerts on the part?

An electron moves with a speed of 8.0 × 10⁶ m/s along the +x-axis.It enters a region where there is a magnetic field of 2.5 T,directed at an angle of 60° to the +x-axis and lying in the xy-plane. ,m_el = 9.11 × 10^-31 kg)Calculate the magnitude of (a)the magnetic force on the electron. (b)the acceleration of the electron.

A wire segment 1.2 m long carries a current I = 3.5 A,and is oriented as shown in the figure.The +x-axis points directly into the page.A uniform magnetic field of magnitude 0.50 T pointing toward the -x direction is present as shown.What is the magnetic force vector on the wire segment?

Three particles travel through a region of space where the magnetic field is out of the page,as shown in the figure.The electric charge of each of the three particles is,respectively,

A charged particle of mass 0.0020 kg is subjected to a magnetic field which acts at a right angle to its motion.If the particle moves in a circle of radius at a speed of what is the magnitude of the charge on the particle?

An electron enters a magnetic field of with a velocity perpendicular to the direction of the field.At what frequency does the electron traverse a circular path? (m_el = 9.11 × 10^-31 kg,e = 1.60 × 10^-19C)

A vertical wire carries a current vertically upward in a region where the magnetic field vector points toward the north.What is the direction of the magnetic force on this current due to the field?

An electron moving with a velocity = 5.0 × 10⁷ m/s enters a region of space where perpendicular electric and a magnetic fields are present.The electric field is = .What magnetic field will allow the electron to go through the region without being deflected?

A wire in the shape of an "M" lies in the plane of the paper.It carries a current of 2.0 A,flowing from points A to E,as shown in the figure.It is placed in a uniform magnetic field of 0.75 T in the same plane,directed as shown on the right side of the figure.The figure indicates the dimensions of the wire.What are the magnitude and direction of the force acting on (a)section AB of this wire? (b)section BC of this wire? (c)section CD of this wire? (d)section DE of this wire? (e)the entire wire?

A proton is first accelerated from rest through a potential difference V and then enters a uniform 0.750-T magnetic field oriented perpendicular to its path.In this field,the proton follows a circular arc having a radius of curvature of 1.84 cm.What was the potential difference V? (m_proton = 1.67 × 10^-27 kg,

A uniform magnetic field of magnitude 0.80 T in the negative z direction is present in a region of space,as shown in the figure.A uniform electric field is also present and is set at 76,000 V/m in the +y direction.An electron is projected with an initial velocity ^{in the +x direction.The y component of the initial force on the electron is closest to which of the following quantities?} (e = 1.60 × 10^-19C)

The figure shows a velocity selector that can be used to measure the speed of a charged particle.A beam of particles is directed along the axis of the instrument.A parallel plate capacitor sets up an electric field E,which is oriented perpendicular to a uniform magnetic field B.If the plates are separated by 2.0 mm and the value of the magnetic field is 0.60 T,what voltage between the plates will allow particles of speed 5.0 × 10⁵ m/s to pass straight through without deflection?