Answer
a). when they are in series, voltage = $6\times1.5V=9V$
b). when they are in parallel, voltage = $1.5V$
c). when three in parallel, and this combination is wired in series with the remaining three.
voltage across the parallel voltages = $1.5V$
required voltage =$1.5+1.5\times3=6V$
Work Step by Step
a). when they are in series, voltage = $6\times1.5V=9V$
b). when they are in parallel, voltage = $1.5V$
c). when three in parallel, and this combination is wired in series with the remaining three.
voltage across the parallel voltages = $1.5V$
required voltage =$1.5+1.5\times3=6V$
