Two identical ideal voltmeter A and B are shown in figure. Let `V_(1)` and `V_(2)` be the readings of voltmeter A when switch s is open and cosed respectively.
Similarly `V_(3)` and `V_(4)` be the readings of voltmetter B when 's is closed and open respectively then
`(V_(3)-V_(4)),(V_(1)-V_(2))` is :

Options

A. 2
B. 6
C. 1
D. 3

Answer

C

Explanation

When s open , `V_(1)=V_(4)=(9/45xx30)/2=3` volt
When s closed: `V_(3)=4` volt and `V_(2)=2` volt
`:.(V_(3)-V_(4))/(V_(1)-V_(2))=1`