Answer:
The  magnitude of the  electric field intensity is   
 
Explanation:
From the question we are told that 
     The  voltage is  
     The  thickness of the membrane is   
 
      
Generally the electric field intensity is mathematically represented as 
                 
  substituting values 
                 
                 
 
        
             
        
        
        
Given Information:  
Voltage of circuit A = Va = 208 Volts
Current of circuit A = Ia = 40 Amps
Voltage of circuit B = Vb = 120 Volts
Current of circuit B = Ib = 20 Amps
Required Information:  
Ratio of power = Pa/Pb = ? 
Answer:  
Ratio of power = Pa/Pb = 52/15
Explanation:  
Power can be calculated using Ohm's law
P = VI
Where V is the voltage and I is the current flowing in the circuit.
The power delivered by circuit A is
Pa = Va*Ia
Pa = 208*40
Pa = 8320 Watts
The power delivered by circuit B is
Pb = Vb*Ib
Pb = 120*20
Pb = 2400 Watts
Therefore, the ratio of the maximum power delivered by circuit A to that delivered by circuit B is
Pa/Pb = 8320/2400
Pa/Pb = 52/15