Why do we prefer a potentiometer with longer wire?

Why do we feel thirsty?

Explain the principle on which the working of a potentiometre is based. Why is the use of a potentiometer preferred over that of a voltmeter for measurement of e.m.f. of a cell?

Sometimes the balance point in the potentiometer may not be obtained on the wire of the potentiometer . Under what condition does it happen ?

The resistance of a potentiometer wire of length 10m is 20 ohm. A resistance box and a 2 volt accumulator are connected series with it. Resistance required to be introduced in the box to have a potential drop of one microvolt per millimeter of the potentiometer wire will be

Which material is used for potentiometer wire and why?

For measuing a potential difference it is more logical to use a potentiometer than a voltmeter. Why?

A potentiometer wire of length 100 cm has a resistance of 10Omega . It is connected in series with a resistance and a cell of emf 2V and of negligible internal resistance. A source of emf 10 mV is balanced against a length of 40 cm of the potentiometer wire. What is the value of external resistance ?