Question

A dialectic material is inserted between the plates of a capacitor. The capacitor has an area of 0.02 m^2 and the plates are separated by 0.4 cm. If the dialectic constant is 2.6

a) Calculate the capacitance

b) If the capacitor is connected across a 500 V source, find the change on it and the energy stored on it

c) Find the value of electric field between the plates

Answer 1

The capacitance of a parallel plate capacitor with plates of area A, separated by a distance d and having a dielectric material of dielectric constant k in between the plates is given by
  

a)
And so, putting the given values, (appropriately converting into SI units )

we get the capacitance as

  

b)

If voltage V is applied across a capacitor of capacitance C, then, the charge on the capacitor is given by

And so, given the value of the voltage V = 500 V, the charge on the capacitor is given by
  
  
And the energy stored in the capacitor is given by



c)
Electric field in between the plates is given by