MCQ
Two long parallel wires are at a distance $2d$ apart. They carry steady equal currents flowing out of the plane of the paper, as shown. The variation of the magnetic field $B$ along the line $XX’$ is given by
- A
- ✓
- C
- D
✓
Answer
Correct option: B.
b
(b) If the current flows out of the paper, the magnetic field at points to the right of the wire will be upwards and to the left will be downward. Now magnetic field at $C$, is zero. The field in the region $BX'$ will be upwards $(+ve)$ because all points lying in this region are to the right of both the wires. Similarly, magnetic field in the region $AX$ will be downwards $(-ve)$. The field in the region $AC$ will be upwards $(+ve)$ because points are closer to $A$ compared to $B$. Similarly magnetic field in region $BC$ will be downward $(-ve)$. Graph $(b)$ satisfies all these conditions.
(b) If the current flows out of the paper, the magnetic field at points to the right of the wire will be upwards and to the left will be downward. Now magnetic field at $C$, is zero. The field in the region $BX'$ will be upwards $(+ve)$ because all points lying in this region are to the right of both the wires. Similarly, magnetic field in the region $AX$ will be downwards $(-ve)$. The field in the region $AC$ will be upwards $(+ve)$ because points are closer to $A$ compared to $B$. Similarly magnetic field in region $BC$ will be downward $(-ve)$. Graph $(b)$ satisfies all these conditions.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
According to Bohr's atomic model angular momentum of electron in $5^{th}$ orbit of $H-$ atom is
→In series $LR$ circuit $X_L = 3R$. Now a capacitor with $X_C = R$ is added in series. Ratio of new to old power factor is
→The nucleus ${92^U}^{234}$ splits exactly in half in a fission reaction in which two neutrons are released. The resultant nuclei are
→In standard $YDSE$ setup, a small transparent slab containing material of $\mu = 1.5$ is placed along $AS_2$ (figure). What will be the distance from $O$ of the central maxima $(PO = 1\ m)$ and $(S_1S_2 = d)$
→If more air is pushed in a soap bubble, the pressure in it:
If the dipole with charges $\pm q$ are kept perpendicular to each other inside a closed cube, then the total electric flux emerging out of the cube will be:
→When we double the radius of a coil keeping the current through it unchanged, what happens to the magnetic field directed along its axis at far off points?
The ratio of the forces between two small spheres with constant charge $(a)$ in air $(b)$ in a medium of dielectric constant $K$ is
→A block $A$ kept on an inclined surface just begins to slide if the inclination is $30^\circ $. The block is replaced by another block $B$ and it is found that it just begins to slide if the inclination is $40^\circ :$
→The number of photo electrons emitted for light of a frequency $v ($higher than the threshold frequency $v_0)$ is proportional to:
→