Question

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?

Answer 1

Step-by-step explanation:

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

=