How can three resistors of resistances 2
, 3
, and 6
be connected to give a total resistance of
(a) 4
, and (b) 1 
?
(a) In order to obtain a total resistance of 4 
from three resistors of 2 
, 3 
and 6 
.
Firstly, connect the two resistors of 3 
and 6
in parallel to get a total resistance of 2
which is less than the lowest individual resistance.
(ii) Then the net R from parallel connection is connected in series with the remaining 2 Q resistor to get a total resistance of 4 Q. This is because in series combination:
R = R1+ R2
R = 2 + 2
R = 4
The arrangement of three resistors of 2,3
and 6
which gives a total resistance of 4
can now be represented as follows :
Thus, we can obtain a total resistance of 4
by connecting parallel combination of 3 
and 6 
resistors in series with 2 
resistor.
(b) In order to obtain a total resistance of 1
from three resistors of 2
, 3 
and 6Q, all the three resistors should be connected in parallel. This is because in parallel combination:
