During an Ohm’s law experiment a student passes an increasing current through a piece of nichrome wire.
(i) Predict what will happen to the temperature of the wire as the current is increased. Give a brief reason.
(ii) State and explain how the resistance of the wire will change because of this temperature rise.
(iii) Describe qualitatively how the plotted V–I points will deviate from an ideal straight line as the wire becomes hot.
(iv) Suggest two practical steps the student can take to obtain a straight V–I graph and justify your suggestions.