I have some doubts in electro magnetic induction:-
1) two circular coils have their centred at the same point. the mutual inducatance between them will be maximum when their axes are:
a) perpendicular to each other
b) at 60 deg
c) at 45 deg to each other
d) parallel to each other
2) In a uniform magnetic field of induction B a wire in the form of a semicircle of radius "r" rotates about the diameter of the circle with angular frequency "w". The axis of rotation is perpendicular to the field . if the total resistance of the circuit is "R", the mean power generated per period rotation is :
3) In a L-R circuit , just after the key is closed:-
a) a current starts flowing in the circuit
b) a potential difference is developed across the resistance.
c) e.m.f developed across the e.m.f of the battery
d) a heat is dissipated in the circuit.