有關phy 的問題

today1314

我想問點解畫electric field line 時, positive charge 的field 係向出面????

abc666

The electric field strength at a point of the electric field is defined as the force that would be exerted on a positive test unit charge at that point.

因為科學家define 了positive test charge
positive test charge同positive charge 會repel
所以force向出 electric field 也向出