Question

9. You are an engineer and are building metal objects for a science lab that are supposed to hold charge for a long time. The object should not be

A) insulated from everything else
B) smooth
C) sharp and pointed
D) circular

Answer 1

The object should not be sharp and pointed as it would facilitate the loss of stored charge through corona discharge. For extended charge retention, objects should be smooth with a large radius of curvature and, if a conductor is being charged by induction, it needs proper grounding.

Step-by-step explanation:

You are an engineer and are building metal objects for a science lab that must hold charge for a long time. The object should not be sharp and pointed. Sharp points on conductors facilitate the transfer of charge to the surrounding air or other nearby objects, which is known as corona discharge. This would result in the loss of the stored charge. Objects designed to hold charge for extended periods are typically smooth and have a large radius of curvature to prevent leakage of charge into the air, such as those used in high-voltage transmission lines. Furthermore, when charging a conductor by induction, it is necessary that the conductor is properly grounded, if it's to be left with a net charge opposite to that of the inducing charge, or not grounded if it's to remain neutral.

Answer 2

A) insulated from everything else

Step-by-step explanation:

The objects is supposed to hold the charge for a long time. The only possibility for that to occur is that the charge sticks on the object, and does not flow away from it.

In order for that to make it possible, the object must be insulated from everything else. In fact, if the object is not isolated, it would be able to exchange charge with other objects around: therefore, the charge on the object could be easily transferred to other objects (or otherwise, an opposite-sign charge can be transferred from other objects to the object itself), so the object would not be able to hold its charge.