Suppose now that the stands are conductive, and are grounded. The student follow
ID: 2221521 • Letter: S
Question
Suppose now that the stands are conductive, and are grounded. The student follows the same procedure; first placing the negatively charged Teflon rod on the left stand, then placing a neutral aluminum rod on the right stand: Image: A. Choose the image below that best represents the charge distribution on the aluminum rod in this case. B. What is the final net charge of each object? i. Teflon: ii. Aluminum Rod Explain C. What is the direction of the electric force on each object? i.What is the direction of the electric force on the aluminum rod by the Teflon rod?13 Select a response Left Right This force is zero ii. What is the direction of the electric force on the Teflon rod by the aluminum rod?(Right, Left, Zero Force) iii.The magnitude of the electric force on the aluminum rod by the Teflon rod is 15 Select a response greater than less than equal to that on the Teflon rod by the aluminum rod. (Equal, Greater, Less)Explanation / Answer
The “ground” or the earth has a huge capacitance, and can absorb any charge, positive or negative, in the order of magnitudes that we deal with. It can be considered as an infinite sink or a reservoir. Its potential can be considered to be zero for all practical purposes. (If I remember rightly, for grounding, especially in high tension cables, the neutral wire has to go deep into the ground and generally touches the water table, wherever possible, for fast dissipation of charge.) When a conductor is grounded, its potential becomes same as that of the ground, i.e., zero. If the conductor is not in any external electric field, then the excess charge flows to the ground to make the conductor’s potential zero, and that is why the integral will be zero, if the potential is set to be zero at infinity. Suppose some positive charge is induced on one side of it, and so there is negative induced charge on the other side. Now if it is grounded, the free negative charge flows to the ground but the induced positive charge remains. The potential of the conductor is still zero, because the potential of the conductor is now the sum due to the external field and the induced charge. So, excess charge need not always flow to the ground, but the potential of a grounded conductor is always zero. (That's nice! Forgot that the library has been opened. It's linking the phrase "Electric Field", but does it have to make it title case always?