A Level物理考试高分攻略：电场与电场力复习要点

就读于国内学校的学生, 在申请英国学校时需要提交英国A-level考试成绩。很多考生因此英国A-level考试搞得头疼，小北整理了一些A水准考试高分攻略的相关资讯，一起去看看吧。

Part 1 Electric Field Shapes 电场概念及表示

Electric Field

“An electric field is a region in which particles with charge experience a force”

Field Shape Diagrams

We represent electric fields with diagrams that have conventions (or rules) that need to be followed.

For example:

The field lines (and arrows) show the direction of the force that would be felt by a positive charge at that point in the field. Note that unlike gravitational fields, electric fields can attract or repel objects.

The spacing between the lines shows how strong the field is at that point. In this case it's strongest near to the charge because the lines are closest there.

This field is uniform because the spacing between the lines remains the same throughout the field shown. The field lines are parallel and equispaced.

Part 2 Electric field strength 电场强度

This is defined as the force per unit charge acting at a point in the field. So an equation for it is:

Where:.

E = electric field strength

F = force acting in newtons

q = the charge in coulombs

Units of E: NC-1 or Vm-1 (these are the same thing!!)

(1)匀强电场Uniform Fields

There is one special example you also need to know :

This is a uniform field. The field strength at any point in this field is:

where

V = the pd between the plates

d = the distance separating the plates.

Field strength is a vector - it has direction as well as magnitude.

This is important to remember because in electric fields you can have field strengths acting in different directions due to different signs of charge.

以上就是专家分享的新加坡A水准考试。祝福各位学生可以发挥自己的优点，改善自己的弱点，不断提高A Level物理学习!