Exam 8: Magnetic Forces

A charged particle (m = 5.0 g, q = -70 $\mu$ C) moves horizontally at a constant speed of 30 km/s in a region where the free fall gravitational acceleration is 9.8 m/s2 downward, the electric field is 700 N/C upward, and the magnetic field is perpendicular to the velocity of the particle.What is the magnitude of the magnetic field in this region?

The diagram below shows the position of a long straight wire perpendicular to the page and a set of directions labelled A through H. When the current in the wire is directed up out of the page, the direction of the magnetic field at point P is:

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 positions 2 and 3 the plane of the loop is parallel to the field as shown.The torque on the loop is maximum in:

What current must be maintained in a square loop (50 cm on a side) to create a torque of 1.0 N . m about an axis through its centre and parallel to one of its sides when a magnetic field of magnitude 70 mT is directed at 40 $\degree$ to the plane of the loop?

A proton is accelerated from rest through a potential difference of 150 V.It then enters a region of uniform magnetic field and moves in a circular path (radius = 12 cm).What is the magnitude of the magnetic field in this region?

An electron moves in a region where the magnetic field is uniform and has a magnitude of 80 $\mu$ T.The electron follows a helical path which has a pitch of 9.0 mm and a radius of 2.0 mm.What is the speed of this electron as it moves in this region?

A particle (mass = 2.0 mg, charge = -6.0 $\mu$ C) moves in the positive direction along the x axis with a velocity of 3.0 km/s.It enters a magnetic field of () mT.What is the acceleration of the particle?

An electron has a velocity of 6.0 *106 m/s in the positive x direction at a point where the magnetic field has the components Bx = 3.0 T, By = 1.5 T, and Bz = 2.0 T.What is the magnitude of the acceleration of the electron at this point?

A 2.0-m wire carries a current of 15 A directed along the positive x axis in a region where the magnetic field is uniform and given by B = (30 -40) mT.What is the resulting magnetic force on the wire?

A wire (mass = 50 g, length = 40 cm) is suspended horizontally by two vertical wires which conduct a current I = 8.0 A, as shown in the figure.The magnetic field in the region is into the paper and has a magnitude of 60 mT.What is the tension in either wire?