Electric field and potential: If the electric potential at a point in space is zero, then the electric field at that point must also be zero.

Total internal reflection: An optical fiber made of glass with an index of refraction 1.50 is coated with a plastic with index of refraction 1.30. What is the critical angle of this fiber at the glass-plastic interface?

Spherical mirrors: The spherical side mirror on a car is convex and has a radius of curvature of 25 cm. Another car is following, 20 m behind the mirror. If the height of the car is 1.6 m, how tall is its image?

Total internal reflection: A tank holds a 1.44-m thick layer of oil that floats on a 0.96-m thick layer of brine. Both liquids are clear and do not intermix. Point O is at the bottom of the tank, on a vertical axis. The indices of refraction of the oil and the brine are 1.40 and 1.52, respectively. A ray originating at O reaches the brine-oil interface at the critical angle. What is the distance of this point from the axis?

Cylindrical capacitors: An air-filled capacitor is formed from two long conducting cylindrical shells that are coaxial and have radii of

Force on moving charges: A charge is accelerated from rest through a potential difference V and then enters a uniform magnetic field oriented perpendicular to its path. The field deflects the particle into a circular arc of radius R. If the accelerating potential is tripled to 3V, what will be the radius of the circular arc?

Power: A 1500-W heater is connected to a 120-V line. How much heat energy does it produce in 2.0 hours?

Lenz’s law: In the figure, a straight wire carries a current I. The wire passes through the center of a toroidal coil. If the current in the wire is quickly reduced to zero, the induced current through the resistor R is

Self-inductance: At what rate would the current in a 100-mH inductor have to change to induce an emf of 1000 V in the inductor?

Spheres of charge: A conducting sphere is charged up such that the potential on its surface is 100 V (relative to infinity). If the sphere’s radius were twice as large, but the charge on the sphere were the same, what would be the potential on the surface relative to infinity?