Question

A moving coil galvanometer has a resistance of $ 50\Omega $ and gives full scale deflection for 10 mA. How could it be converted into an ammeter with a full scale deflection for 1 A?

• A. $ 50/99\,\Omega $ in series
• B. $ 50/99\,\Omega $ in parallel
• C. $ 0.01\,\Omega $ in series
• D. $ 0.01\,\Omega $ in parallel

Answer 1

Answer: (B)

$ S=\frac{{{i}_{g}}\times G}{i-{{i}_{g}}}=\frac{10\times {{10}^{-3}}\times 50}{1-{{10}^{-3}}\times 10} $ $ =\frac{50}{99}\Omega $ in parallel