Six Cells each of emf 2V and internal resistance $ 0.2\Omega $ are connected as shown in the figure. The reading of the ideal voltmeter is 

zero 

$\text{Let Current I flow in the closed loop from A to D }$

$ \text{Applying Kirchoff loop law } 2 - 0.2I +2 -0.2I +2-0.2I + 2 -0.2I + 2 -0.2I + 2 -0.2I = 0 $

$ \Rightarrow 1.2 I = 12 $

$ I = \frac{12}{1.2} = 10A$

$ \text{Reading of voltmeter is P.D between point A and D } $

$\Rightarrow V = 2 - 0.2 I = 0V$