Energy in the Electric Field: Each plate of a parallel-plate air-filled capacitor has an area of 0.0040 m2, and the separation of the plates is 0.020 mm. An electric field of 8.2 × 106 N/C is present between the plates. What is the energy density in the region between the plates? (?0 = 8.85 × 10-12 C2/N ? m2)
A. 300 J/m3
B. 200 J/m3
C. 400 J/m3
D. 500 J/m3
E. 610 J/m3
Answer: A
You might also like to view...
Suppose a small M type star (mass less than 0.1 solar masses) is orbiting an invisible object in space. The radius of the orbit is 2.0 A.U., the period is 2.0 years. How massive is the invisible object? Could it be a burned out white dwarf star?
What will be an ideal response?
Intensity: A sinusoidal electromagnetic wave is propagating in vacuum. At a given point and at a particular time the electric field is in the +x direction and the magnetic field is in the -y direction, and at that point the intensity of the wave is 0.45 W/m2. (c = 3.0 × 108 m/s, ?0 = 4? × 10-7 T ? m/A, ?0 = 8.85 × 10-12 C2/N ? m2) (a) What is the direction of propagation of the wave?(b) What is the electric field amplitude at the given point?
What will be an ideal response?
What eventually halts the gravitational collapse of an interstellar gas cloud that forms a brown dwarf rather than a true (main-sequence) star?
A) The central object becoming hot enough to sustain nuclear fusion in its core B) Degeneracy pressure caused by the high density of electrons in the core C) Thermal pressure from the high core temperature D) The onset of convection in the object's outer layers
The figure shows two forces acting at right angles on an object. They have magnitudes = 6.3 N and = 2.1 N. What third force will cause the object to be in equilibrium (acceleration equals zero)?
A) 6.6 N at 162° counterclockwise from 1 B) 6.6 N at 108° counterclockwise from 1 C) 4.2 N at 162° counterclockwise from 1 D) 4.2 N at 108° counterclockwise from 1