Dielectrics: A parallel-plate capacitor has a capacitance of 10 mF and charged with a 20-V power supply. The power supply is then removed and a dielectric material of dielectric constant 4.0 is used to fill the space between the plates. How much energy is now stored by the capacitor?

Ampere’s law: A hollow cylinder with an inner radius of

Thin lenses: It is desired to project the image of an object four times its actual size using a lens of focal length 20 cm. How far from the lens should the object be placed?

Resonance: For an LRC series circuit containing a resistance of a capacitance of and an inductance of what frequency is needed to minimize the impedance?

Total internal reflection: The speed of light in a material is

Radiation pressure: A 22.0-kg mirror with a surface area of 1.0 m2 and a

Internal battery resistance: In the figure a current of 6.0 A is drawn from the battery. What is the terminal voltage Vab of the battery?

Thin lenses: In the figure, the thin lens forms a real image of the object 94.0 cm from the object. What is the focal length of the lens?

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?