Exam 24: Magnetic Fields and Forces

A very long straight current-carrying wire produces a magnetic field of 20 mT at a distance d from the wire.To measure a field of 5 mT due to this wire,you would have to go to a distance of:

A square wire 2.0 cm on each side is oriented so that a 5.00 mT magnetic field makes a 30.0º angle with the normal to the plane of the square.If a 1.0 mA current causes a 32.0 N · m torque on the wire,how many loops does the wire make?

The magnitude of a magnetic field a distance 3.0 µm from a wire is 20.0 × 10^-4 T.How much current is flowing through the wire? Assume the wire is the only contributor to the magnetic field.

If a charged particle moves at right angles to a magnetic field,it experiences a force.How can the particle have an acceleration if the kinetic energy remains constant?

The net magnetic field inside a conductor must be zero.

Alpha particles (charge = +2e,mass = 6.68 × 10^-27 kg)are accelerated in a cyclotron to a final orbit radius of 0.50 m.The magnetic field in the cyclotron is 0.50 T.The kinetic energy of an alpha particle in the final orbit is closest to:

A rigid rectangular loop,which measures 0.30 m by 0.40 m,carries a current of 5.5 A,as shown.A uniform external magnetic field of magnitude 2.9 T in the negative x-direction is present.Segment CD is in the x-z plane and forms a 35° angle with the z-axis,as shown.An external torque applied to the loop keeps it in static equilibrium.The magnitude of the external torque is closest to:

A very short solenoid contains N = 20 circular loops of wire.The radius of the loop is R = 0.5 meters,and the length of the solenoid is d = 0.02 meters.Approximately what is the magnetic field in the center of the solenoid?

A 5 m length of wire carrying a current of 5 A lies on a horizontal table with a rectangular top of dimensions 0.300 m × 0.400 m.The ends of the wire are attached to opposite ends of a diagonal of the rectangle.A vertical magnetic field of 0.30 T is present.What magnetic force acts on this segment of wire?

A negatively charged particle is moving to the right,directly above a wire having a current flowing to the right,as shown below.In which direction is the magnetic force exerted on the particle?

How far from the center of a wire carrying a 2.0 A current does the magnetic field that results from the current have a magnitude of 4.0 × 10^-5 T?

Two parallel,straight wires are 7.0 cm apart and each carries a 18.0 A current in the same direction.One wire is securely anchored,and the other is attached in the center to a movable cart.If the force needed to move the wire when it is not attached to the cart is negligible,with what force does the wire pull on the cart? Both wires are 50.0 m long.

A wire carrying a current is shaped in the form of a circular loop of radius 4.0 mm.If the magnetic field strength at its center is 1.1 mT with no external magnetic fields contributing to it,what is the magnitude of the current that flows through the wire?

A particle with a charge of 1 C experiences a force FBin a magnetic field.A second particle follows it at the same velocity.If the second particle has a charge of -2C,what force does it experience?

Consider a solenoid of length L,N windings,and radius b (L is much longer than b).A current I is flowing through the wire.If the radius of the solenoid were doubled (becoming 2b),and all other quantities remained the same,the magnetic field

A long straight wire has a constant current flowing to the right.A square ring is situated above the wire,and also has a constant current flowing through it (as shown).Which of the following statements is true?

An electron in a magnetic field has a cyclotron frequency of 8.0 × 10¹² Hz.What is the magnetic field strength? (The mass of an electron is 9.1 × 10^-31 kg,and the charge of an electron is 1.6 × 10^-19 C. )

A rigid rectangular loop,which measures 0.30 m by 0.40 m,carries a current of 9.9 A,as shown.A uniform external magnetic field of magnitude 1.8 T in the negative x-direction is present.Segment CD is in the x-z plane and forms a 19° angle with the z-axis,as shown.The y-component of the magnetic force on segment AB is closest to:

Two particles with equal mass,one carrying a charge q and the other -2q,each enter at right angles to a uniform magnetic field with the same velocity.Which is deflected into a circular path with the larger radius?

A metallic weight is suspended from a metal spring.If now a current is passed through the spring,