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 Ï€ ,
So , B
= ( u˳ I ) / 2 Ï€ ,
And u˳ = 4
Ï€ 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 ,
. . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. .
