In an experiment, to study the dependence of potential difference (V) on the electric current (I) across a conductor (resistor), if the circuit is on for long time, then-select two correct options from the following :
(i) Zero error of an ammeter will be changed.
(ii) Zero error of a voltmeter will be changed.
(iii) Value of a resistance will be changed.
(iv) Resistor will be heated.