Exam 22: Magnetic Forces and Magnetic Fields

The planetary model of the hydrogen atom consists of an electron in a circular orbit about a proton.The motion of the electron of charge 1.60 *10 ^{- 19} C creates an electric current.The radius of the electron orbit is 5.30 *10 ^{- 11} m and the electron's velocity is 2.20 * 10⁶ m/s.What is the magnetic field strength at the location of the proton?

A positively charged particle has a velocity in the negative z direction at point P.The magnetic force on the particle at this point is in the negative y direction.Which one of the following statements about the magnetic field at point P can be determined from this data?

A long cylindrical wire (radius = 2.0 cm)carries a current of 40 A that is uniformly distributed over a cross section of the wire.What is the magnitude of the magnetic field at a point which is 1.5 cm from the axis of the wire?

The magnetic moment of an electron (charge = -e;mass = m_e)moving in a circular orbit of radius r with speed v about a nucleus of mass m_N is proportional to

An ideal solenoid of radius a has n turns per unit length and current I.The magnetic flux $\phi$ _B through any circular area of radius a inside the solenoid,centered on and perpendicular to the solenoid axis is

A long hollow cylindrical conductor (inner radius = 2.0 mm,outer radius = 4.0 mm)carries a current of 24 A distributed uniformly across its cross section.A long wire which is coaxial with the cylinder carries an equal current in the opposite direction.What is the magnitude of the magnetic field 3.0 mm from the axis?

A segment of wire of total length 2.0 m is formed into a circular loop having 5.0 turns.If the wire carries a 1.2-A current,determine the magnitude of the magnetic field at the center of the loop.

What is the magnitude of the magnetic field at point P if a = R and b = 2R?

A long wire lies in a tangle on the surface of a table,as shown below.When a current is run through the wire as shown,the largest component of the magnetic field at X points

A hollow cylindrical (inner radius = 1.0 mm,outer radius = 3.0 mm)conductor carries a current of 80 A parallel to its axis.This current is uniformly distributed over a cross section of the conductor.Determine the magnitude of the magnetic field at a point that is 2.0 mm from the axis of the conductor.

A 2.0-C charge moves with a velocity of ( $2.0 \tilde { \mathbf { i } } + 4.0 \tilde { \mathbf { j } } + 6.0 \tilde { \mathbf { k } }$ )m/s and experiences a magnetic force of ( $4.0 \hat { \mathbf { i } } - 20 \hat { \mathbf { j } } + 12 \hat { \mathbf { k } }$ )N.The x component of the magnetic field is equal to zero.Determine the z component of the magnetic field.

A charged particle (mass = M,charge = Q > 0)moves in a region of space where the magnetic field has a constant magnitude of B and a downward direction.What is the magnetic force on the particle at an instant when it is moving horizontally toward the north with a speed V?

Three particles of equal charge,X,Y,and Z,enter a uniform magnetic field B.X has velocity of magnitude v parallel to the field.Y has velocity of magnitude v perpendicular to the field.Z has equal velocity components v parallel and perpendicular to the field.Rank the radii of their orbits from least to greatest.

Equal currents of magnitude I travel into the page in wire M and out of the page in wire N.Eight directions are indicated by letters A through H. The direction of the magnetic field at point P is

A long solenoid (1 000 turns/m)carries a current of 25 mA and has an inside radius of 2.0 cm.A long wire which is parallel to and 4.0 cm from the axis of the solenoid carries a current of 6.0 A.What is the magnitude of the magnetic field at a point on the axis of the solenoid?

An electron follows a circular path (radius = 15 cm)in a uniform magnetic field (magnitude = 3.0 G).What is the period of this motion?

A particle (q = 5.0 nC,m = 3.0 $\mu$ g)moves in a region where the magnetic field has components B_x = 2.0 mT,B_y = 3.0 mT,and B_z = -4.0 mT.At an instant when the speed of the particle is 5.0 km/s and the direction of its velocity is 120 $\degree$ relative to the magnetic field,what is the magnitude of the acceleration of the particle?

A current loop is oriented in three different positions relative to a uniform magnetic field.In position 1 the plane of the loop is perpendicular to the field lines.In position 2 and 3 the plane of the loop is parallel to the field as shown.The torque on the loop is maximum in

If a = 2.0 cm,b = 5.0 cm,and I = 20 A,what is the magnitude of the magnetic field at the point P?

Which of the following type(s)of materials is(are)repelled when a magnet is brought near by?