JEE Advance - Physics (2009 - Paper 1 Offline - No. 20)
Six point charges, each of the same magnitude q, are arranged in different manners as shown in Column II. In each case, a point M and a line PQ passing through M are shown. Let E be the electric field and V be the electric potential at M (potential at infinity is zero) due to the given charge distribution when it is at rest. Now, the whole system is set into rotation with a constant angular velocity about the line PQ. Let B be the magnetic field at M and $$\mu$$ be the magnetic moment of the system in this condition. Assume each rotating charge to be equivalent to a steady current.
Column I | Column II | ||
---|---|---|---|
(A) | $$E=0$$ | (P) | ![]() Charge are at the corners of a regular hexagon. M is at the centre of the hexagon. PQ is perpendicular to the plane of the hexagon. |
(B) | $$V\ne 0$$ | (Q) | ![]() Charges are on a line perpendicular to PQ at equal intervals. M is the midpoint between the two innermost charges. |
(C) | $$B=0$$ | (R) | ![]() Charges are placed on two coplanar insulating rings at equal intervals. M is the common centre of the rings. PQ is perpendicular to the plane of the rings. |
(D) | $$\mu \ne 0$$ | (S) | ![]() Charges are placed at the corners of a rectangle of sides a and 2a and at the mid points of the longer sides. M is at the centre of the rectangle. PQ is parallel to the longer sides. |
(T) | ![]() Charges are placed on two coplanar, identical insulating rings are equal intervals. M is the midpoint between the centres of the rings. PQ is perpendicular to the line joining the centres and coplanar to the rings. |
Explanation
Case (P) : $$E=0,V=0, B=0,\mu=0$$.
Case (Q) : $$E\ne0,V=0, B=0,\mu=0$$.
Case (R) : $$E=0,V\ne0, B\ne0,\mu\ne0$$.
Case (S) : $$E=0,V\ne0, B\ne0,\mu\ne0$$.
Case (T) : $$E\ne0,V=0, B=0,\mu=0$$.
Hence, $$\mathrm{(A)\to(P),(R),(S);(B)\to(R),(S);(C)\to(P),(Q),(T);(D)\to(R),(S)}$$Comments (0)
