Kirchoff's law of current states that algebraic sum of all currents meeting at a single point is . . . . . . . . , A ) finite , B ) infinite , C ) zero , D ) None of these ,

1 ) Ampere’s Law : -

Ampere’s law states that when current is passed

through conductor , so magnetic field is produced .

B  α  I , 1 / r   .

So  ,  B  α  I / r  ,

So ,   B =  kI / r  ,

∴    k  =  u˳ / 2 π  ,

So ,   B  =   ( u˳ I )  /  2 π  ,

And  u˳ =  4 π  x  10^( -7 ) ,  wb / A · m   .

And it is called permeability of free space .

 

2 ) Kirchoff's law of current states that algebraic sum of all currents meeting at a single point is . . . . . . . . ,

A ) finite ,                                                                   B ) infinite ,

C ) zero ,                                                                    D ) None of these ,

Correct Answer : -   C ) zero ,

 

3 ) In voltmeter , conduction takes place due to electrons only .

 

4 ) Collisions of free electrons with atoms or ions of conductor cause heat.

 

5 ) The conductivity of super conductor is . . . . . . . . . ,

A ) finite ,                                                                   B ) infinite ,

C ) zero ,                                                                    D ) None of these ,

Correct Answer : -   B ) infinite ,

 

6 ) On increasing temperature , conductivity of semiconductor will . . . . . . . ,

A ) increased ,                                                                      B ) decreased ,

C ) no change ,                                                                     D ) None of these ,

Correct Answer : -   A ) increased ,

 

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