Q.

The maximum resistance which can be made using four resistors each of resistance 12Ω is

1 2 Ω  
2 1 Ω  
3 2.5 Ω  
4 8 Ω  

Ans.

(1)

The maximum resistance which can be made using four resistors each of resistance 12Ω is 2Ω. This can be explained as:  In series combination, the current in each resistor remains constant and the voltage gets added up. As a result, the individual resistances also get added up.

So, Equivalent Resistance =R1+R2+R3+R4

                                           =12+12+12+12=42=2Ω