Answer:
a).β=0.53
T
a).β=0.40 
T
Explanation:
The magnetic field at distance 'r' from the center of toroid is given by:
a).
b).
The distance is the radius add the cross section so:
The incorrect statement about electromagnetic waves is C. induction of electric fields by changing magnetic fields only occurs if a conducting material is present.
Electromagnetic waves do not rely on any medium for propagation, which means that the generation of fields is irrespective of the presence of a conducting material.
Neutrons have a zero charge but consist of mass.
The correct option is A.
Fluorescent lamps have many advantages over incandescent lamps and the options given in B, C and D are part of these advantages. The option given in A is a disadvantage and not an advantage. This is because, as a result of operating at an higher temperature, it will gives out and radiate more heat.
