$H _{ p }=\left[\frac{ V ^2}{\left(\frac{ R }{2}\right)}\right) t =\frac{2 V ^2 t }{ R }$
Series combination
$H _s=\left(\frac{ V ^2}{2 R }\right) t \quad \therefore \frac{ H _{ p }}{ H _{ s }}=4$


Reason : An ideal voltmeter draws almost no current due to very large resistance, and hence $(V)$ and $(a)$ will read zero.

