Question

how does the resistance of a metallic wire depend on its temperature explain with reason?

Answer 1

Length of the wire  Inside the wire there are fixed positive ions they don't move around so when eletrons moving inside the wire collide with these fixed positive ions which causes resistance.So if the length of the wire is more so eletrons will have to travel more distance so the no. of collosions with fixed positive ions will be more so resistance increases.

Area of the wire  If the area (thinkness) of wire is more then the no. of collosion with the fixed positive ions will be less since they get more space to pass through with less collosions.

Temperature of the wire  If the temperature of the wire rises then the fixed positive ions start to vibrate about their mean position so the no. of the collosions with the eletrons will be more.                                                                                                                                           

If you are writing this answer then plz dont forget to write fixed positive ions 

The eletrons collide with fixed positve ions which cause resistance ...... this is written for your understanding no need to write this line in answer paper.

hope this helps you dear ☺️☺️☺️☺️☺️

Answer 2

the resistance of metallic wire depends on it's temperature because when the current passes through the metallic wire the molecules of wire joint together tightly when current passes through it it's creates friction which causes temperature increase so by the increasement of temperature it may be chance of break down......hope u like it if yes mark me as branliest answer