Author: Anonymous

  Switch S in the circuit shown above has been closed for a long time. Suppose that the switch is opened for a time t = 0. Which of the following combinations of a differential equation and an initial condition can be used to solve for the charge Q(t) on the upper plate of the capacitor as a function of time t? A rectangular circuit loop is shown with a battery on the left side labeled epsilon. Along the top wire is a switch labeled S. On the right side of the loop, a resistor labeled R is placed vertically. Inside the loop, a capacitor labeled C is connected vertically between the top and bottom wires. The bottom wire connects back to the battery.

A coil of wire contains of 20 turns, each with an area of 1.5 x 10-3 m2. A magnetic field is normal to the surface of each loop. Initially, the magnitude of B is 0.050 T. During the period of time of 0.10 s, the magnitude of the field at the coil has increased to 0.060 T. What is the average emf induced in the coil during this time?

Two identical light bulbs are connected in series and hooked up to a 110 V constant voltage source. The current through each bulb is 0.25 A. Find the resistance of a single light bulb.

As the temperature of a metal conductors increases, its resistance __________.

A parallel plate capacitor has capacitance of 100 pF. The area of each plate is 100 mm2. What is the spacing between the two plates.

_____________ relates the rate of change of flux to an induced emf.

Two long, hollow, concentric conducting cylinders carry currents in opposite directions into and out of the plane of the page, as shown in the cross section above. The currents are unequal, but the current density J is the same for both cylinders. In which of the following regions can the net magnetic field be zero at some nonzero finite distance r from the central axis? Four concentric circles are centered at the same point. The innermost circle has radius R and is unshaded. The region between R and 2R is marked with x symbols and labeled J. The region between 2R and 3R is unshaded. The region between 3R and 4R is filled with dot symbols and also labeled J.

Point charge A carries a charge of +8 C. Point charge B has a charge of +1 C. When the charges are 1 meter apart, they exert a force F on each other. The charge on B is increased to +4 C. How far apart should the charges be placed so that force F between the charges remains the same?

The 500 gram mass carries a charge of -7 x 10-8 C. If the coefficient of friction between the mass and the surface is 0.20, and an electric field of magnitude 3 x 107 N/C is horizontal and directed to the right, which is being treated as the positive x-direction. What is the acceleration of the mass?

An electron traveling at a velocity v enters a uniform magnetic field B. Initially, the velocity and field are perpendicular to each other. If the electron goes a distance d, the amount of work done on it by the magnetic field is ________.