physics 2 chapter 15 – Flashcards

if the object, ends up with a positive charge, then it is missing electrons. if it is missing electrons, then it must have been removed form the object during the rubbing process.

the nucleus is the central part of the atom. removing protons would thus require removing entire atoms and perhaps removal of protons form the nucleus. however, removing electrons requires neither removing entire atoms no removing pieces of the nucleus. thus transfer of charge usually involves transfer of electrons.

the charge will be on the outside of the sphere since it is a conductor. thus when the person touches the inside, nothing will happen either. intact, even is there is charge on the inside of the sphere, nothing will happen either.

if there is alot of oxygen around, anything that is flammable will be able to burn very easily. even a small source might be enough to start the fire in the presence of so much oxygen. conductive shoes prevent the accumulation of charge on the body of the wearer. rubber shoes would encourage charge accumulation. if the person is carrying a charge, they might cause a discharge when they touch just about anything else. this, in combination with the oxygen and fuel source, could start a fire.

One might think that both objects need to be charged, and oppositely charged at that, but that's not quite the case. Bringing a charged object close to a neutral object can attract charges of opposite sign in the neutral object, and at the same time repel charges of like sign. Since the charges of opposite sign in the neutral object are now closer to the charged object than the charges of like sign, there is a net attractive force! Note that it doesn't matter what sign of charge is on the charged object. The force between a charged object and a neutral object, when it exists, is always attractive. The slight separation of charges in the neutral object caused by the charged object is called an "induced charge."

Bring the positively charged object near but not touching the metal object. This attracts negative charges in the metal object leaving the opposite end positively charged (though over-all it's still neutral). Now touch the opposite end of the metal object. The positive charges there attract electrons from your body. Since you are touching the metal object, the electrons from your body can travel into the metal object. Now remove your hand. This leaves the metal object with excess electrons, even when the positively charged object is moved away. This is charging by induction.

No charge exists at point A. All of the charge is at q1 or q2. No force exists there since there is nothing on which to exert a force. But yes, an electric field does exist there. The electric field embodies the capability to exert a force. And certainly if a charge was placed as A, the other two would exert a force on it. So the electric field does exist there.

If the field is pointing towards the ground, the ground must have a negative charge. (Electric fields point away from positive charges, toward negative charges.)

The charge in the comb induces dipoles in the paper. The dipoles are attracted to the charge on the comb. When the paper touches the comb, some charge is transferred from the comb making the paper now charged with charges of the same sign. Thus they now repel and fly away from the comb.

This gives any electrical charge that gets to the antenna a path to follow other than into your TV. For example, a lightning bolt.

The reason a room can be electrically shielded by surrounding it with a conductor is that there is no electric field within the conductor. There is no corresponding principle for gravitation. There are no "mass conductors." When you put a mass around another mass, gravity works just fine inside. (Try it yourself. Seal yourself in your dorm room. You still weigh the same...)

The net flux is positive, thus the net charge inside the surface must be positive. That's about all you can conclude: the net charge is non-zero and positive.

electric charges moe freely in response to an electric force. copper, aluminum, and silver.

all other materials like glass and rubber are charged by rubbing.

1. distance r, between them 2. it is proportional to the product of the magnitude the charges q1, and q2 3. like charges repel and unlike charges attract

?1.60×10?¹? C

+1.60×10?¹? C

applies only to point charges and spherical distributions of charges, in which case r is the distance between the two centers of charge.

6/18=1/3 q2 is 3x larger than q1

q2 is positive, the point away q1 is negative the lines point towards