text: Question
  
  # A thin spherical shell with radius R1 = 4.00cm is concentric with a larger thin spherical...
  
  A thin spherical shell with radius R1 = 4.00cm is concentric with a larger thin spherical shell with radius 7.00cm . Both shells are made of insulating material. The smaller shell has charge q1=+6.00nC distributed uniformly over its surface, and the larger shell has charge q2=?9.00nC distributed uniformly over its surface. Take the electric potential to be zero at an infinite distance from both shells.
  
  Part A
  
  What is the electric potential due to the two shells at the following distance from their common center: r = 0?
  
  Part B
  
  What is the electric potential due to the two shells at the following distance from their common center: r = 5.00cm?
  
  Part C
  
  What is the electric potential due to the two shells at the following distance from their common center: r = 8.00cm?
  
  Part D
  
  What is the magnitude of the potential difference between the surfaces of the two shells?
  
  Part E
  
  Which shell is at higher potential: the inner shell or the outer shell?
  
  part A) at r = 0 ,
  
  The electric potential, V = k*q1/R1 + k*q2/R2
  
  = 9*10^9*6*10^-9/0.04 + 9*10^9*(-9*10^-9)/0.07
  
  part B) at r = 5 cm
  
  The electric potential, V = k*q1/r + k*q2/R2
  
  = 9*10^9*6*10^-9/0.05 + 9*10^9*(-9*10^-9)/0.07
  
  part C) at r = 8 cm = 0.08 m
  
  The electric potential, V = k*q1/r + k*q2/r
  
  = 9*10^9*6*10^-9/0.08 + 9*10^9*(-9*10^-9)/0.08
  
  part D)
  
  potential differenec between the two shells,
  
  delta_V = potential on inner sphere - potential on outer sphere
  
  = (k*q1/R1 + k*q2/R2) - (k*q1/R2 + k*q2/R2)
  
  = k*q1*(1/R1 - 1/R2)
  
  = 9*10^9*6*10^-9*(1/0.04 - 1/0.07)
  
  part E) The inner shell.