A moving coil galvanometer has $$50$$ turns and each turn has an area $$2$$×$$10$$−$$4m2$$. The magnetic field produced by the magnet inside the galvanometer is $$0.02T$$. The torsional constant of the suspension wire is $$10$$−$$4Nm$$ rad−$$1$$. When a current flows through the galvanometer, a full scale deflection occurs if the coil rotates by $$0.2rad$$. The resistance of the coil of the galvanometer is $$50$$Ω. This galvanometer is to be converted into an ammeter capable of measuring current in the range $$0$$−$$1.0A$$. For this purpose, a shunt resistance is to be added in parallel to the galvanometer. The value of this shunt resistance, in ohms,is…..

Question

A moving coil galvanometer has $$50$$ turns and each turn has an area $$2$$×$$10$$−$$4m2$$. The magnetic field produced by the magnet inside the galvanometer is  $$0.02T$$. The torsional constant  of the suspension wire is  $$10$$−$$4Nm$$ rad−$$1$$. When a current flows through the galvanometer, a full scale deflection occurs if the coil rotates by  $$0.2rad$$. The resistance of the coil of the galvanometer is  $$50$$Ω. This galvanometer is to be converted into an ammeter capable of measuring current in the range  $$0$$−$$1.0A$$. For this purpose, a shunt resistance is to be added in parallel to the galvanometer. The value of this shunt resistance, in ohms,is…..

Infinity Learn · Accepted Answer

N $$=$$ $$50$$ turns                        $$A=2$$×$$10$$−$$4$$ $$m2$$                    $$B=0.02$$ T                    $$K=10$$−$$4$$ $$Qm=0.2$$ rad                        $$Rg=50$$Ω                         $$IA=0-1.0A$$               τ$$=MB=C$$θ      here $$M=NIASo$$ , $$BINA=C$$θ                         ⇒$$0.02$$×ig×$$50$$×$$2$$×$$10$$−$$4=10$$−$$4$$×$$0.2$$                 ⇒$$Ig=0.1AFor$$ galvanometer, resistance is to be connected to ammeter in shunt.The resistance to be connected in parallel to ammeter.Ig×$$Rg=I$$−IgS      ⇒$$0.1$$×$$50=1$$−$$0.1S$$     ⇒$$S=509=5.555$$Ω$$=5.56$$ ohm

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