question_answer

A voltmeter has a resistance of G ohms and range V volts. The value of resistance used in series to convert it into a voltmeter of range nV volts is [MP PMT 1999; MP PET 2002; DPMT 2004; MH CET 2004]

A)                    nG                                    

B)            \[(n-1)G\]

C)                    \[\frac{G}{n}\]             

D)            \[\frac{G}{(n-1)}\]

Correct Answer: B

Solution :

             Suppose resistance R is connected in series with voltmeter as shown. By Ohm's law \[{{i}_{g}}.R=(n-1)V\] Þ \[R=(n-1)G\] (where \[{{i}_{g}}=\frac{V}{G})\]