Answer :
Ammeter is connected in series with a resistance or an element of a circuit, in which we need to measure the current. So the resistance of the meter should be as low as possible in order not to increase resistance of the circuit...
Let r be the internal resistance of the ammeter. A small resistance S is connected in parallel with the ammeter. Then the effective resistance of the ammeter with the shunt resistance = R = r S / (r +s)
R < S as well as R < r
we choose S so small that effective resistance is less than that...and is negligible.
Let r be the internal resistance of the ammeter. A small resistance S is connected in parallel with the ammeter. Then the effective resistance of the ammeter with the shunt resistance = R = r S / (r +s)
R < S as well as R < r
we choose S so small that effective resistance is less than that...and is negligible.