Everything Science Grade 11

17.5 CHAPTER 17. ELECTROSTATICS

Electric field in a capacitor ESBHR

The electric field strength between the plates ofa capacitor can be calculated using the formula:
E =Vd
where E is the electric field in J.C−^1 , V is the potential difference in volts (V) and d is the distance
between the plates in metres (m).

Example 11: Electric field in a capacitor

QUESTION

What is the strength of the electric field in a capacitor which has a potential difference of

300V between its parallel plates that are 0 ,02m apart?

SOLUTION

Step 1 : Determine what is required

We need to determine the electric field betweenthe plates of the capacitor.

Step 2 : Determine how to approach the problem

We can use the formula:

E =Vd

Step 3 : Determine what is given.

We are given the potential difference and the distance between the plates.

Step 4 : Determine the electricfield

E =

V

d

=

300

0 , 02

= 1, 50 × 104 J.C−^1

Exercise 17 - 2

1. Determine the capacitance of a capacitor which stores 9 × 10 −^9 C when a potential difference
   of 12 V is applied to it.


2. What charge will bestored on a 5 μF capacitor if a potentialdifference of 6V is maintained
   between its plates?