Consider the two idealised systems (i) a parallel plate capacitor with large plates and small separation and (ii) a long solenoid of length `LgtgtR` radius of cross-section In (i) E is ideally treated as a constant between plates and zero outside. In (ii) magnetic field is constant the solenoid and zero outside. these idealised assumptions, however, contradict fundamental laws as below

Options

A. Case (i) contradicts Gauss law for electrostatic fields
B. Case (ii) contradicts Gauss law for magnetic fields
C. Case (i) agrees with `oint` E.dl = 0
D. Case (ii) contradicts `oint` H.dl = `I_("en")`

Answer

B

Explanation

As Gauss law states `oint_(s) E` ds = `(q)/(epsi_(0))` for electrostatic field . It does not contradict for electrostatic fields as the electric field lines do not form continuous closed path. According to Gauss law in magnetic field,
`oint_(s) = E.ds = 0`
It contradicts for magnetic field, because there is a magnetic field inside the solenoid and no field outside the solenoid carrying current but the magnetic field lines from the closed path.