CLASS 12 chapter 3 , question based on resistance .

Questions on resistance

1.    Calculate the resistance of an aluminum wire of length 60cm and cross sectional area 1.0mm² . The resistivity of aluminum is 2.6x10^-8Ω-m.

Ans . 0156 Ω        

2.    At 27 degree centigrade the resistance of a resistor is 83 Ω . what is the temperature of the resistor if the resistance is found to be 100 Ω and the temperature coefficient of the material of the resistor is 1.7 x 10^-4 per degree centigrade ?                                        ans 1241 degree centigrade

3.    A conductor rail has a cross sectional of 15m² and resistivity of 7.6x 10^-8 Ωm at 0 degree centigrade . if the temperature coefficient of resistance of the material of the conductor is 0.005 per degree centigrade ,calculate its resistance per km when the temperature is 50 degree centigrade .

Ans 0.063 Ω

4.    A potential difference V is applied across a conductor of length l . how is the drift velocity affected ,when Vis doubled and length is half.

Cbse 2010     ans 4Vd

5.    A conductor of length L is connected to a D.C source of emf ( e ) if the length of conductor is tripled by stretching it , keeping emf constant , explain . how its drift velocity would be affected .   CBSE 2015