Question

Electric current is sent through a resistance of 20 ohm from a battery of EMF 2 volt and of negligible internal resistance . During measurement of current with the help of ammeter ,20% error is incurred .What is the resistance of the ammeter ?

Answer 1

Total resistance (without ammeter resistance) = 20 ohm

Battery Voltage = 2V

Theoretically current through the circuit = 2/20
=0 .1A

20% error occurred in the ammeter
0.1×20% = 0.02A

So the reading will be = 0.08 A

​​​​​So total Resistance including Ammeter =2/0.08 =25

So Ammeter Resistance = 25-20 = 5 ohm