Haryana PMT Haryana PMT Solved Paper-2010

  • question_answer A moving coil galvanometer is converted into an ammeter reading up to 0.03 A by connecting a shunt of resistance 4r across it. and into an ammeter reading up to 0.06 A when a shunt of resistance r is connected across it. What is the maximum current which can be sent through this galvanometer if no shunt is used?

    A)  0.01 A                                  

    B)  0.02 A

    C)  0.03 A                                  

    D)  0.04 A

    Correct Answer: B

    Solution :

                    For an ammeter \[\frac{{{i}_{g}}}{i}=\frac{S}{G+S}\] \[\Rightarrow \]               \[{{i}_{g}}G=(i-{{i}_{g}})S\] \[\therefore \]  \[{{i}_{g}}G=(0.03-{{i}_{g}})4r\] ???(i) and        \[{{i}_{g}}G=(0.06-{{i}_{g}})r\]    ...(ii)    From Eqs. (i) and (ii)                   \[0.12-4{{i}_{g}}=0.06-{{i}_{g}}\]  \[\Rightarrow \]         \[{{i}_{g}}=0.02A\]              


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