Electric Field

1. What's electric field? (please explain it in a simple and easy-read way.)

In physics, an electric field is the effect (attractive or repulsive force) produced by the existence of an electric charge.
-------------------------
2. In electric field, are the field lines represented to the direction flow of the surrounding charges?

The direction of field lines indicates the direction of motion of a positive charge if such a charge is placed in the field.
----------------------------
3. Refer to Q2, where do the charges come from? Do they exist naturally in the surroundings? Or, they simply come from an charged object?

There must be charge(s) present in order to establish an electric field. The established field will then have interaction on other charges that happen to be at the vicinity.

Electric field is the electric force acting PER unit positive test charge. It is a vector quantity and has a unit of NC-1.

In words, the electric field is a region in which charges can experience electric force.


2. The electric field lines DOES NOT represent the direction flow of the surrounding charges.

It just represent the direction flow of the acceleration of the surrounding charges, but not the velocity.


3. Charges come from charged object. They do not exist naturally in the surroundings. That means, charges exist in the presence of charge carriers.



2008-09-14 15:33:12 補充：
1. 電場是作用於每一個單位正測試電荷的電磁力。它是一個向量，單位是NC^-1
電場是一個電荷能感應電磁力的區域。

2008-09-14 15:34:06 補充：
2. 電場場線並不代表附近電荷的流動方向。
它是代表電荷加速的方向，並不是速度。

2008-09-14 15:35:04 補充：
3. 電荷來自有電荷的物件，它們並不獨立存在。即電荷必須有電荷攜帶媒體才能存在。

2008-09-14 15:35:30 補充：
Some mistakes were made in Q.2
It should be:
It just represent the direction of the acceleration of the surrounding charges, but not the velocity.