Answer:
a)14.17V
b)32.8 x  J
J
c)96.9x  J
J
d) -64x  J
J
Explanation:
Given:
Area 'A'=7.10cm² =>7.1 x  m²
m²
voltage ' '=4.8 volt
'=4.8 volt
 = 2.20mm => 2.2 x
 = 2.20mm => 2.2 x  m
m
 = 6.50mm => 6.5 x
 = 6.50mm => 6.5 x  m
m
a) Capacitance  before push is given by:
 before push is given by:
  = εA/
 = εA/ =>
 =>
  =   2.85 x
 =   2.85 x  F
 F
  =
=
 => 2.85 x
=> 2.85 x  x 4.8
 x 4.8
 =1.37 x
=1.37 x  C
 C
Capacitance  after push is given by:
 after push is given by:
  = εA/
 = εA/ =>
 =>
  =   9.66 x
 =   9.66 x  F
F
 =
=
  =
=
 
 
Therefore, the potential difference between the plates
 = 1.37 x
 = 1.37 x  / 9.66 x
 / 9.66 x  =>14.17V
 =>14.17V
b) 
 32.8 x
 32.8 x  J
J
c)
 = 96.9x
= 96.9x  J
J
d) the work required to separate the plates is given by:
workdone=   -
- => 32.8 x
=> 32.8 x  J- 96.9x
J- 96.9x  J
J
W≈ -64x  J
J