A neutral conductor contains a hollow cavity in which there is a +90.0 nC point charge. A charged rod then transfers -30.0 nC to the conductor. Afterward, what is the charge. . .
. . . on the inner wall of the cavity?
. . . on the exterior surface of the conductor?
Solution
Let’s call the charge on the inner wall Qin, the charge on the outer wall Qout, the total
charge of the conductor Qc, and the charge of the point-charge Qp.
To begin, recall two special properties of a conductor: its charge is distributed over its
surface(s), and the electric field inside it is zero.
The first tells us that Qc = Qout + Qin.
The second implies that the electric flux, Φe, through any Gaussian surface that is
entirely within a conducting material is also necessarily zero. Suppose we consider such
a surface surrounding the cavity. As noted, because the surface is entirely within the
conducting material, Φe = 0. By Gauss’s law, however, we know Φe = Qenc/0, where
Qenc = Qin + Qp is the total charge contained within the surface. Hence, we have
0 = Qin + Qp, or Qin = −Qp.
Together, these give
Qin = −Qp
Qout = Qc − Qin = Qc + Qp.
Given Qc = −50 nC and Qp = 100 nC, this gives Qin = −100 nC and Qout = 50 nC.

Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.

An isolated conducting spherical shell carries a positive charge. part a which statement (or statements) about the electric field and the electric potential inside and outside the spherical shell is correct? which statement (or statements) about the electric field and the electric potential inside and outside the spherical shell is correct? electric potential inside the shell is constant and outside the shell is changing as 1/r2 both the electric potential and the electric field does change with r inside and outside the spherical shell electric potential inside and outside the shell is constant, but not zero electric potential inside the shell is constant and outside the shell is equal to zero electric field inside and outside the shell is constant (does not change with the position r), but is not equal to zero electric field inside and outside the shell is changing as 1/r (where r is the distance from the center of the sphere) electric field inside is equal to zero and outside the shell is constant, but not zero electric potential inside the shell is constant and outside the shell is changing as 1/r electric field inside and outside the shell is changing as 1/r2 electric field inside is equal to zero and outside the shell is changing as 1/r2 electric field inside and outside the shell is zero electric field inside is constant and outside the shell is changing as 1/r

When is a current produced? when the terminals of an electrochemical cell are connected by a wire if the electric circuit is opened in an electrochemical cell if the electrolyte is removed from an electrochemical cell when the electrodes are reversed in an electrochemical cell