In a parallel plate air capacitor, the distance between plates is red...
The capacitance of a parallel plate air capacitor is given by C
0 = ε
0A/d …(i)
Whore, ε0 = permittivity of the medium,
A = area of plates
and d = distance between the plates
When the distance between plates is reduced and a dielectric slab is introduced, then capacitance becomes
C = Kε0A/d1 …(ii)
where, K = dielectric constant of the medium.
Here, K = 2, d1 =d/4 and C0 = 4μF = 4 x 10-6F
From Eq. (ii), we get
= 4KC0 …(iii) [from Eq. (i)]
Substituting given values in Eq. (iii), we get C = 4 x 2 x 4 = 32 μF
In a parallel plate air capacitor, the distance between plates is red...
Explanation:
Given, initial capacitance of the parallel plate air capacitor, C = 4 μF
The distance between the plates is reduced to one fourth, i.e., d' = d/4
The dielectric constant of the medium filled between the plates is 2.
We know that the capacitance of a parallel plate capacitor is given by:
C = ε0A/d
where ε0 is the permittivity of free space, A is the area of the plates and d is the distance between the plates.
New Capacitance:
The new capacitance of the capacitor can be found using the formula:
C' = ε0A/d'
where d' is the new distance between the plates.
Since the area of the plates and the permittivity of free space remain constant, we have:
C' = C(d/d')
Substituting the given values, we get:
C' = 4(4/1) = 16 μF
Effect of dielectric medium:
When a dielectric material is introduced between the plates of a capacitor, the capacitance increases. The capacitance of the capacitor with a dielectric medium can be given by:
C' = kε0A/d'
where k is the dielectric constant of the material and ε0 is the permittivity of free space.
Substituting the given values, we get:
C'' = 2ε0A/(d/4) = 8ε0A/d
Therefore, the new capacitance of the capacitor with the dielectric medium is 8 times the initial capacitance.
Final Answer:
The new capacitance of the capacitor when the distance between plates is reduced to one fourth and the space between them is filled with a dielectric medium of constant 2 is:
C'' = 16 x 8 = 32 μF
Hence, the correct answer is option (a) 32 μF.