A cubic block of metal, 14.0 cm on each side, has a spherically-shaped cavity in
ID: 2183960 • Letter: A
Question
A cubic block of metal, 14.0 cm on each side, has a spherically-shaped cavity in its interior. The cavity has a radius of 4.00 cm. (A cut-away view of the block of metal is shown in the figure.) A point charge of q = -0.300 mu C is placed at the center of the cavity. What is the magnitude and direction of the electric field at point P1, which is 2.00 cm from the center of the spherical cavity? What is the magnitude and direction of the electric field at point P2, which is 5.00 cm from the center of the spherical cavity? Give a general description of what you think the electric field looks like outside of the block of metal. At what locations do charges accumulate in the metal, and what is the magnitude and sign of the charges that accumulate at those locations ? Figure 6 - A cut-away view of a cubic block of metal, 14.0 cm on each side, with a spherical cavity in its interior of radius 4.00 cm. A point charge of q = -0.300 mu C is placed at the center of the cavity.Explanation / Answer
a.E = Kq /r^2 = 8.9X 10^9 X 0.3 X 10^-6 / 0.002^2 = 6675000 in the radially inward direction b. since the point P2 is inside the metal, there is no electric field inside the cube. so, E=0 . c. outside the block, the field lines are coming into the block , perpendicular to the surface of the block . d. the charge accumulates, at the spherical surface of the inner hollow. it is positive in nature . the charge also accumulates on the surface of the block. it is negative in nature , to keep the net charge on the block zero.