Question

A galvanometer may be converted into ammeter or voltmeter. In which of the following cases
the resistance of the device will be the largest?
(Assume maximum range of galvanometer $=$ 1 mA)

• A. an ammeter of range 10A
• B. a voltmeter of range 5 V
• C. an ammeter of range 5 A
• D. a voltmeter of range 10 V.

Answer 1

Answer: (D)

a voltmeter of range 10 V.

As shown in figure 1,

$v=I_g{R}_x=1\times {10}^{-3}\times R_x$

As $R_x=$very large voltmeter,$v_0$ range will be more.

Maximum voltage may be of range 10v.