A magnetic field $$\overrightarrow{\mathrm{B}}=\mathrm{B}_{0} \hat{j}$$ exists in the region $$a < x < 2 a$$ and $$\overrightarrow{\mathrm{B}}=-\mathrm{B}_{0} \hat{j}$$, in the region $$2 a < x < 3 a$$, where $$\mathrm{B}_{0}$$ is a positive constant. A positive point charge moving with a velocity $$\vec{v}=v_{0} \hat{i}$$, where $$v_{0}$$ is a positive constant, enters the magnetic field at $$x=a$$. The trajectory of the charge in this region can be like,

Two wires each carrying a steady current I are shown in four configurations in Column I. Some of the resulting effects are described in Column II. Match the statements in Column I with the statements in Column II and indicate your answer by darkening appropriate bubbles in the $$4 \times 4$$ matrix given in the ORS.

	Column I		Column II
(A)	Point P is situated midway between the wires.	(P)	The magnetic fields (B) at P due to the currents in the wire are in same direction.
(B)	Point P is situated at the mid-point of the line joining the centers of the circular wires, which have same radii.	(Q)	The magnetic fields (B) at P due to the currents in the wires are in opposite directions.
(C)	Point P is situated at the mid-point of the line joining the centers of the circular wires, which have same radii.	(R)	There is no magnetic field at P.
(D)	Point P is situated at the common center of the wires.	(S)	The wires repel each other.

$$ \text { Match the following Columns. } $$

In a moving coil galvanometer, torque on the coil can be expressed as $$\tau=k i$$, where $$i$$ is current through the wire and $$k$$ is constant. The rectangular coil of the galvanometer having numbers of turns $$\mathrm{N}$$, area $$\mathrm{A}$$ and moment of inertia I is placed in magnetic field B. Find

(A) $$k$$ in terms of given parameters $$\mathrm{N}, \mathrm{I}, \mathrm{A}$$ and B;

(B) The torsional constant of the spring, if a current $$i_{0}$$ produces a deflection of $$\frac{\pi}{2}$$ in the coil;

(C) The maximum angle through which coil is deflected, if charge $$\mathrm{Q}$$ is passed through the coil almost instantaneously. (Ignore the damping in mechanical oscillations.)