Two identical current-carrying coaxial loops carry current \(I\) in an opposite sense. A simple amperian loop passes through both of them once. Calling the loop as \(C,\)
(a) \(\oint B\cdot dl= \mp 2\mu_0 I\)
(b) the value of \(\oint B\cdot dl\) is independent of the sense of \(C\).
(c) there may be a point on \(C\) where \(B\) and \(dl\) are perpendicular.
(d) \(B\) vanishes everywhere on \(C\).

 
Which of the above statements is correct?

1. (a) and (b) 2. (a) and (c)
3. (b) and (c) 4. (c) and (d)
Subtopic:  Ampere Circuital Law |
Level 3: 35%-60%
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Consider the two idealized systems: (i) a parallel plate capacitor with large plates and small separation and (ii) a long solenoid of length \(L >>R\), radius of cross-section. In (i) \({E}\) is ideally treated as a constant between plates and zero outside. In (ii) magnetic field is constant inside the solenoid and zero outside. These idealised assumptions, however, contradict fundamental laws as below:
1. case (i) contradicts Gauss's law for electrostatic fields.
2. case (ii) contradicts Gauss's law for magnetic fields.
3. case (i) agrees with \(\oint {E} \cdot {d} {l}=0\)
4. case (ii) contradicts \(\oint{H} \cdot {d} {l}=I_{e n}\)
Subtopic:  Ampere Circuital Law |
 54%
Level 3: 35%-60%
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