A circuit contains an ammeter, a battery of $$30$$ V and a resistance $$40.8$$ ohm all connected in series. If the ammeter has a coil of resistance $$480$$ ohm and a shunt of $$20$$ ohm, the reading in the ammeter will be

Question

Infinity Learn · Accepted Answer

The circuit shown in the figure.Resistance of the ammeter $$isRA=(480$$Ω$$)(20$$Ω$$)(480$$Ω$$+20$$Ω$$)=19.2$$Ω (As$$ $$480$$Ω and $$20$$Ω are in $$parallel)  As ammeter is in series with $$40.8$$Ω , ∴   Total resistance of the circuit is $$R=40.8$$Ω$$+RA=40.8$$Ω$$+19.2$$Ω$$=60$$ΩBy Ohm's law, Current in the circuit is $$I=VR=30$$ $$V60$$Ω$$=12$$ $$A=0.5$$ AThus the reading in the ammeter will be  $$0.5$$  A.

A circuit contains an ammeter, a battery of 30 V and a resistance 40.8 ohm all connected in series. If the ammeter has a coil of resistance 480 ohm and a shunt of 20 ohm, the reading in the ammeter will be

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