The coil of a galvanometer has a resistance of 18.2 Ω, and its meter deflects full scale when a current of 6.78 mA passes through it. To make the galvanometer into an ammeter, a 26.9-mΩ shunt resistor is added to it. What is the maximum current that this ammeter can read?

Question

Milagros Nolan

Physics

22 March, 22:37

The coil of a galvanometer has a resistance of 18.2 Ω, and its meter deflects full scale when a current of 6.78 mA passes through it. To make the galvanometer into an ammeter, a 26.9-mΩ shunt resistor is added to it. What is the maximum current that this ammeter can read?

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Jocelyn Marshall · Answer 1

Ammeter is used in series in a circuit. It has two resistances in parallel. They are 18.2 ohm and. 0269 ohm. For full scale deflection, current of. 00678 A passes in 18.2 ohm.

potential over it

= 118.2 x. 00678

=.801396 V

Same volt will act on. 0269 ohm shunt which is in parallel

current in it

.801396 /.0269 A

= 29.79 A

Total current

29.79 +.00678

= 29.79678

=