A moving coil galvanometer has 50 turns and each turn has an area 210 . The magnetic field produced by the magnet inside the galvanometer is 0.02 . The torsional constant of the suspension wire is 10 . When a current flows through the galvanometer, a full scale deflection occurs if the coil rotates by 0.2 . The resistance of the coil of the galvanometer is 50 . This galvanometer is to be converted into an ammeter capable of measuring current in the range 01.0 . For this purpose, a shunt resistance is to be added in parallel to the galvanometer. The value of this shunt resistance, in , is __________.

Answer

5.55 o 5.56

Explanation

If the maximum deflection in galvanometer is for current `I_(g)`, then torque on coil for this current is equal to torsional torque due to twist of 0.2 rad.
`implies(NI_(g)A)(B)=C thetaimplies I_(g)=((10^(-4))(0.2))/((50)(2xx10^(-4))(0.02))=0.1A`
For conversion into ammeter of range `0.1A`
`(0.1)R_(g)=(0.9)R_(s), R_(s)=50/9-5.555Omega`