Question

13: Question 11. - 10.0 pts possible Which of the following capacitors, each of which has plates of area A, would store the most charge on the top plate for a given po- tential difference V? V d/2 1. Air V 2. d/2 T Glass V d/2 3. Vacuum V d Glass - 5. Vacuum

Answer 1

Given, there are 5 capacitors
All of them have potential difference V applied to them , and have plate areas A
Now, Capacitance of a parallel plate capacitor is given by C = k*A*epsilon/d
where k is dielectric constant of the material in the capacitor, A is plate area, epsilon is permittivity of free space and d is plate seperation
now,
charge on capacitor is given by
Q = CV = kA*epsilon*V/d
so Q depends on k/d for constant A and V
for 1, k = 1.1 (Air), d = d/2 , hence Q1 = k'(2.2/d) [ k' = A*epsilon*V]
similiarly

for 2, d = d/2, k = 6
hence, Q2 = k'(12/d)

for 3, d = d/2, k = 1 Q3 = k'(2/d)

for 4, d = d, k = 6, Q4 = k'(6/d)
for 5, d = d, k = 1, Q5 = k'(1/d)

hence, we can see
Q2 > Q4 > Q1 > Q3 > Q5
hence, most charge will be stored on capacitor 2, which has dielectric as well as least plate seperation