Correct Answer: Both A and R are true and R is correct explanation of A
4. The core of a solenoid is made of material of relative permeability ?r. A small cavity area dA and length dl is cut in the core. If it is desired that flux density in the cavity should be equal to B0
Options
A. the fields inside and outside the cavity must be equal
B. the field inside the cavity must be made stronger than field outside the cavity
C. the field inside the cavity must be made weaker than the field outside the cavity
Correct Answer: the field inside the cavity must be made stronger than field outside the cavity
5. A conductor carries 10 A current in + x direction and is lying in a field having a flux density 0.2 T directed along + z direction. The magnitude of force per metre length and direction are
7. An electron is moving around a proton, in a circle of radius R. If flux density in the region is increased from zero to B, the force on the electron is
