A milli voltmeter of 25 milli volt range is to be converted into an ammeter of 25 ampere range. The value (in ohm) of necessary shunt will be

• Correct answer
  A

  $0.001$
• B

  $0.01$
• C

  1
• D

  $0.05$

Solution

Galvanometer is converted into ammeter, by connected a shunt, in parallel with it.
$$ \begin{array}{l} \frac{G S}{G+S}=\frac{V_{G}}{I}=\frac{25 \times 10^{-3}}{25} \\ \frac{G S}{G+S}=0.001 \Omega \end{array} $$ Here $S < G$ so $S=0.001 \Omega$

Hence, the correct answer is option: 'A'.