Four cells eac h of emf 1.9 V and internal resistance 1 ohm are connected to an external resistance of 18 ohm as shown in the fig. FInd the terminal potential difference of this combination.

Four cells each of emf 1.9 V and internal resistance 1 ohm 

E= 1.9 V

r=1 Ω

 

 

 

 

Hence, the circuit becomes

 

 

Total internal resistance of the cell in a row

r'=1+1=2 Ω

Total resistance of the circuit,

R'=R+r'

R'=18+2=20 Ω

Therefore, the current in the circuit,

 

Hence, P.D should be 3.42 V according to given conditions.