Why do we prefer a potentiometer with longer wire?

Why do we prefer to use a wrench with a long arm?

Why do we prefer mercury in a barometer?

Why do we need Quantum theory?

What is a potentiometer? Would you prefer a voltmeter or a potentiometer to measure the e.m.f. of a battery?

What is potentiometer?Would you prefer a voltmeter or a potentiometer to measure the e.m.f of a battery?

You are given a potentiometer, a rheostat, one key, a driving cell for potentiometer, one galvanometer, two cells of unknown e.m.f., one two way key and some connecting wires. Using all those given drawa circuitdiagram for finding j the ratio ofthe e.m.fofthe two cells.