A …………… is either used to detect the presence of a weak current or to only know the direction of flow of current in a circuit.
(a) ammeter
(b) galvanometer
(c) voltmeter
(d) rheostat

(b) galvanometer

Reason — A galvanometer is used to either detect the presence of a weak current or to only know the direction of flow of current in a circuit. It does not measure the magnitude of current in a circuit.