Question

PA COLLEG ) The The istance fa metal wire changrs with nesintance of s wire is inversely proportional o the lenh ofv 1Which one of the following statements concerning A) Below its critical temperature, the resistiviry of s superconducso in e B) Critical temperstures for some superconduciors esceed 100 K ) All materials are superconducting at temperatures neat abechune D) A emf. constant current can be maintained in a supecondacing in fo e yan wht ED Superconductors are perfect conductors 21. Which one of the following statements concermng pemanem-n A) The north pole of a permanent magnet ie amracted o a south pole B) All permanent magnets are surrounded by magnenc feld Q The direction of a magnetic field is indicated by the nonth ple ofs comp D) Magnetic ficeld lines outside a permanent maom the noth pde and end on the south pole 12 When a permanent magnet is cut in hal,epece wil bh pke andne piece will be south pole 22 Which combination of units can be uned to espeshe 23. Which one of the fillowvingng the agnetic fonce on a charged particle in a magnetic field is true A) The magnetic force is a maximum if the panicle is tationary B) The magnetic force is sers if the paricle moves perpendicular so the feld Q) The magnetic fionce is a maximom if the particle moves parallei to the feld D The magnetic force acts in the direction of motion for a positovely charged parmice ED The magnetc force depends on the compooens of the paricle's velocity that is perpendicular to the field 24 Complete the fillowring statement The magninude of the magnetic force thst acts otn a chatgod particle in s magnetic field is independent of M the sign of the charge B) the magnitude of the charge

Answer 1

20. Resistance of a metal wire is changing with temperature because most of the metals have a positive temperature coefficient. Which means that as the temperature increases the resistance of a metal resistor or metal wire increses as well.

So, option (C) is correct.